| de Damborenea J, Conde A, Rodriguez-Donoso G, Agulló-Rueda F and Arenas MA (2025), "Thermal shock resistance of additive manufactured Inconel 718 by concentrated solar energy", Sci. Rep.., March, 2025. Vol. 15, pp. 7557. Nature Publishing Group. |
| Abstract: Concentrated Solar Power (CSP) is a powerful tool for simulating the extreme high-temperature conditions that metallic materials encounter. Using a vertical parabolic solar furnace, it was possible to perform heating and cooling cycles between 250 and 950 textdegreeC in approximately 250 s per cycle. This capability is particularly relevant for the development of solar receivers used in solar thermal plants. Additive Manufacturing (AM) offers the potential to create new compositions and geometries that can enhance the efficiency of these solar receivers. In this study, Ni-base superalloystextemdashidentified as suitable materials for high-temperature solar receiverstextemdashwere produced using AM and tested in two conditions: as-built and after thermal treatment. These were compared with a forged reference alloy. The results revealed the formation of a protective oxide layer on the surface in all cases. However, the oxide layer on the samples fabricated by additive manufacturing appeared to be more compact and adherent compared to that formed on the reference alloy. |
BibTeX:
@article{Damborenea20250304SCRP7557,
author = {de Damborenea, Juan and Conde, Ana and Rodriguez-Donoso, Gloria and Agulló-Rueda, Fernando and Arenas, Maria Angeles},
title = {Thermal shock resistance of additive manufactured Inconel 718 by concentrated solar energy},
journal = {Sci. Rep.},
publisher = {Nature Publishing Group},
year = {2025},
volume = {15},
pages = {7557},
url = {https://doi.org/10.1038/s41598-025-92332-x},
doi = {10.1038/s41598-025-92332-x}
}
|
| Solana I, Ynsa MD, Agulló-Rueda F, Sánchez-Prieto J, Grojo D, Siegel J and Garcia-Lechuga M (2025), "Silicon amorphization responses by combined irradiations with MeV ion beams and ultrashort laser pulses", Surf. Interfaces., May, 2025. Vol. 69, pp. 106772. Elsevier. |
| Abstract: This work demonstrates a significant synergistic effect between MeV ion implantation and femtosecond laser irradiation in silicon amorphization. The achievable amorphization depth and the range of laser fluencies leading to amorphization is increased for implanted samples in comparison to pristine silicon. In Si(100) samples, prior to femtosecond laser irradiation (800 nm and 120 fs, or 1030 nm and 180 fs) ion-induced defects are produced with protons (0.6, 1 and 2 MeV) or Si-ions (2 MeV) at varying ion-irradiation fluences. Then, the investigated defects densities before laser irradiation range from low levels to levels approaching ion-induced amorphization (defects per atom, dpa, from 10-9 to 0.1). The optimal pre-conditioning for subsequent femtosecond laser-induced amorphization is found at a moderate defect density level, dpa = 10^-5. Additionally, it is shown that the achievable spatial resolution of the synergistic material amorphization is determined by the high resolution of the focused ion irradiation, suggesting a potential pathway for high-resolution patterning based on laser-assisted techniques. However, at high defect densities (dpa ≈ 0.1), the synergistic effect diminishes, and femtosecond laser irradiation instead reduces disorder, indicating a defect-annealing effect rather than further amorphization. |
BibTeX:
@article{Solana20250521SFIN,
author = {Solana, Irene and Ynsa, M. Dolores and Agulló-Rueda, Fernando and Sánchez-Prieto, Jesús and Grojo, David and Siegel, Jan and Garcia-Lechuga, Mario},
title = {Silicon amorphization responses by combined irradiations with MeV ion beams and ultrashort laser pulses},
journal = {Surf. Interfaces},
publisher = {Elsevier},
year = {2025},
volume = {69},
pages = {106772},
url = {https://doi.org/10.1016/j.surfin.2025.106772},
doi = {10.1016/j.surfin.2025.106772}
}
|
| Fernández García A, Garcia-Lechuga M, Agulló-Rueda F, Rubio Zuazo J and Manso Silvan M (2024), "Femtosecond laser thinning for resistivity control of tungsten ditelluride thin-films synthesized from sol-gel deposited tungsten oxide", Surf. Interfaces., November, 2024. Vol. 44, pp. 103668. Elsevier. |
| Abstract: In this work we present a route for fabricating WTe_2 thin-films together with femtosecond laser post processing, enabling to finely control the conductivity. First, we produce amorphous films of WO_3 on Si by spin-coating a sol-gel precursor followed by a consolidating annealing and a reduction process in partial H_2 atmosphere, leading to porous metallic tungsten cluster layers. To achieve WTe_2, the films were exposed to the chalcogen vapours by isothermal closed space vapor transport. The formation of a tungsten ditelluride film composed of piled crystals could be confirmed and a gradient of surface rich Te identified through hard X-ray photoelectron spectroscopy. Finally, it is demonstrated that resistivity can be changed from 0.2 mΩ.m to 1 mΩ.m, while keeping the material characteristics. An anisotropic conductivity can be induced by direct selective thinning with fs laser writing (350 fs pulse duration, 515 nm laser wavelength) of 1D stripes. The obtained results, demonstrate that laser processing is a promising thin-film post-processing technique that can be applied to 2D transition metal dichalcogenide thin films. |
BibTeX:
@article{FernandezGarcia20231122SI,
author = {Fernández García, A. and Garcia-Lechuga, M. and Agulló-Rueda, F. and Rubio Zuazo, J. and Manso Silvan, M.},
title = {Femtosecond laser thinning for resistivity control of tungsten ditelluride thin-films synthesized from sol-gel deposited tungsten oxide},
journal = {Surf. Interfaces},
publisher = {Elsevier},
year = {2024},
volume = {44},
pages = {103668},
url = {https://doi.org/10.1016/j.surfin.2023.103668},
doi = {10.1016/j.surfin.2023.103668}
}
|
| Fernández-Garcia A, García-Lechiga M, Fernández-Alonso FJ, Ariza R, Agulló-Rueda F, Maldonado N, Ynsa MD, Solís J and Manso-Silván M (2024), "MicroPIXE characterization of out-of-plane 2D molybdenum diselenide nanosheets grown on ultrafast laser-structured substrates", In 19th International Conference on Nuclear Microprobe Technology and Applications (ICNMTA2024), Madrid, 14--19th July 2024. |
BibTeX:
@inproceedings{FernandezGarcia2024ICNMTA1,
author = {Fernández-Garcia, Alejandro and García-Lechiga, Mario and Fernández-Alonso, Francisco Javier and Ariza, Rocio and Agulló-Rueda, Fernando and Maldonado, Noelia and Ynsa, María Dolores and Solís, Javier and Manso-Silván, Miguel},
title = {MicroPIXE characterization of out-of-plane 2D molybdenum diselenide nanosheets grown on ultrafast laser-structured substrates},
booktitle = {19th International Conference on Nuclear Microprobe Technology and Applications (ICNMTA2024), Madrid, 14--19th July 2024},
year = {2024},
url = {https://icnmta2024madrid.com/}
}
|
| Magro R, Muñoz-Noval A, Briz Monago JA, Murias JR, Espinosa Rodr\iguez A, Fraile LM, Agulló-Rueda F, Ynsa MD, Tavares de Sousa C, Cortés Llanos B, Garc\ia López GM, Nacher E, Garc\ia Tavora V, Mont i Geli N, Nerio A, Valladolid Onecha V, Pallás R, Tarifeno-Saldivia A, Tengblad O, Manso Silvan MJ and Viñals i Onsés S (2024), "Iodine substituted hydroxyapatite nanoparticles and activation of derived ceramics for range verification in proton therapy", J. Mater. Chem. B., October, 2024. Vol. 12(46), pp. 12030-12037. The Royal Society of Chemistry. |
| Abstract: Osteosarcoma is a radioresistant cancer and proton therapy a promising radiation alternative to treat cancer with the advantage of high dose concentration in the tumor area. In this work, we propose the use of iodine substituted hydroxyapatite nanomaterials (IHAP) to use iodine (127I) as a proton radiation tracer giving access to range verification studies in mineralized tissues. For this purpose, the nanomaterials were synthesized at four iodine concentrations by hydrothermal synthesis. The material is characterized using different microstructural techniques to identify an optimal high iodine concentration and pure apatite phase nanomaterial. Finally, such pure IHAP powders were shaped and irradiated with proton beams of 6 and 10 MeV and their activation demonstrated through subsequent decay analysis. The materials could be integrated in phantom structures for the verification of doses and range of protons prior to animal testing and clinical proton therapy treatments of tumors located deep under combined soft and calcified tissue. |
BibTeX:
@article{Magro20241015JMCHB,
author = {Magro, Raul and Muñoz-Noval, Alvaro and Briz Monago, Jose Antonio and Murias, Javier R. and Espinosa Rodr\iguez, Andrea and Fraile, Luis M. and Agulló-Rueda, Fernando and Ynsa, M. D. and Tavares de Sousa, Celia and Cortés Llanos, Belén and Garc\ia López, Gastón M. and Nacher, Enrique and Garc\ia Tavora, Vicente and Mont i Geli, Nil and Nerio, Amanda and Valladolid Onecha, Victor and Pallás, Ramón and Tarifeno-Saldivia, Ariel and Tengblad, Olof and Manso Silvan, Miguel Jose and Viñals i Onsés, Silvia},
title = {Iodine substituted hydroxyapatite nanoparticles and activation of derived ceramics for range verification in proton therapy},
journal = {J. Mater. Chem. B},
publisher = {The Royal Society of Chemistry},
year = {2024},
volume = {12},
number = {46},
pages = {12030--12037},
url = {https://doi.org/10.1039/D4TB01391C},
doi = {10.1039/D4TB01391C}
}
|
| Mendez-González Y, Agulló-Rueda F, Torres-Costa V, García AF, Guerra JDS and Silvan MM (2024), "Influence of the synthesis method on the microstructural properties of Ta modified AgNbO_3 ferroelectric thin films", Curr. Appl. Phys.., December, 2024. Vol. 59, pp. 10-17. North-Holland. |
| Abstract: Lead-free Ag(Nb_0.80Ta_0.20)O_3 (ANT) thin films were synthesized via a chemical solution deposition process by the spin-coating technique. The effect of two different heat-treatment methods on the structural and microstructural properties was systematically investigated. X-ray diffraction and Raman spectroscopy results revealed that the orthorhombic perovskite structure was successfully obtained for the film crystallized by the conventional heat-treatment cycle. Secondary phases, however, associated with (Nb,Ta)_2O_5, Ag_8(Nb,Ta)_26O_69, Ag_2(Nb,Ta)_8O_21, Ag_2(Nb,Ta)_4O_11 phases and metallic Ag ion were detected for the rapidly annealed film. The surface microstructure is noticeably influenced by the crystallization method, revealing a change in the morphology of the grains for the studied samples. The expected cationic and oxygen stoichiometries, as well as the homogeneity of microstructure in-depth, were confirmed using the Rutherford backscattering. The nanoscale ferroelectric response has been investigated from piezoelectric force microscopy analysis, detecting a clear domain structure for the studied ANT films. |
BibTeX:
@article{MendezGonzalez202412CAP,
author = {Mendez-González, Y. and Agulló-Rueda, F. and Torres-Costa, V. and García, A. Fernández and Guerra, J. D. S. and Silvan, M. Manso},
title = {Influence of the synthesis method on the microstructural properties of Ta modified AgNbO_3 ferroelectric thin films},
journal = {Curr. Appl. Phys.},
publisher = {North-Holland},
year = {2024},
volume = {59},
pages = {10--17},
url = {https://doi.org/10.1016/j.cap.2023.12.008},
doi = {10.1016/j.cap.2023.12.008}
}
|
| Mendez González Y, Agulló-Rueda F, Torres-Costa V, Fernández García A, Guerra JDS and Manso Silvan M (2024), "Structural and microstructural characterizations of Ta modified AgNbO_3 ferroelectric thin films", Vacuum.
[BibTeX] |
BibTeX:
@article{MendezGonzalez2024VCM,
author = {Mendez González, Yanela and Agulló-Rueda, F. and Torres-Costa, V. and Fernández García, A. and Guerra, J. D. S. and Manso Silvan, M.},
title = {Structural and microstructural characterizations of Ta modified AgNbO_3 ferroelectric thin films},
journal = {Vacuum},
year = {2024},
note = {submitted}
}
|
| Naveas N, Pulido R, Graber T, Martin-Palma R, Agulló-Rueda F, Brito I, Garc\ia MÁ, Sevilla MT, Hernández-Montelongo J, Muñoz-Noval Á, Marini C, Soriano L, Sánchez-Marcos J and Manso-Silván M (2024), "Experimental and theoretical investigation of the treatment of Cu-rich acid mine drainage using iron oxide magnetic nanoparticles", J. Environ. Chem. Eng.., August, 2024. Vol. 12(5), pp. 113822. Elsevier. |
| Abstract: Acid Mine Drainage (AMD) is a significant environmental problem in the mining industry due to its high concentration of hazardous metals and metalloids, sulfate compounds, and low pH levels. Despite the attention that iron oxide magnetic nanoparticles (MNP) have received for AMD remediation, there is still a lack of understanding of the physicochemical mechanisms behind their non-specific adsorption, particularly in distinct variations of AMD, such as Cu-rich AMD. In this study, we synthesized, characterized, and applied MNP to the two-step treatment of Cu-rich AMD. The chemical and physical properties of the MNP and magnetically separated sludges after AMD treatment are characterized. Additionally, the chemical species adsorbed onto the MNP, the oxidation state of the resultant sludge after Cu-rich AMD treatment, and the short-range ordering of metal contaminant species on the surface of the MNP are identified. Finally, first-principles calculations using Density Functional Theory were conducted to understand how different Cu ion species adsorb to the MNP surface depending on the pH of the Cu-rich AMD. The bonding between MNP and Cu species occurs primarily through metal cation-oxygen bonds on the surface of MNP, and this bonding is influenced by the pH of the solution. A combination of experimental and theoretical approaches was the key to arrive at this conclusion. This information can aid in the comprehension of how metal contaminants adhere to the surfaces of MNP and in the precise engineering of these nanoparticles. |
BibTeX:
@article{Naveas20240812JECE,
author = {Naveas, Nelson and Pulido, Ruth and Graber, Teófilo and Martin-Palma, Raúl and Agulló-Rueda, Fernando and Brito, Iván and Garc\ia, Miguel Ángel and Sevilla, Mar\ia Teresa and Hernández-Montelongo, Jacobo and Muñoz-Noval, Álvaro and Marini, Carlo and Soriano, Leonardo and Sánchez-Marcos, Jorge and Manso-Silván, Miguel},
title = {Experimental and theoretical investigation of the treatment of Cu-rich acid mine drainage using iron oxide magnetic nanoparticles},
journal = {J. Environ. Chem. Eng.},
publisher = {Elsevier},
year = {2024},
volume = {12},
number = {5},
pages = {113822},
url = {https://doi.org/10.1016/j.jece.2024.113822},
doi = {10.1016/j.jece.2024.113822}
}
|
| Naveas N, Pulido R, Torres-Costa V, Agulló-Rueda F, Santibáñez M, Malano F, Recio-Sánchez G, Garrido-Miranda KA, Manso-Silván M and Hernández-Montelongo J (2023), "Antibacterial Films of Silver Nanoparticles Embedded into Carboxymethylcellulose/Chitosan Multilayers on Nanoporous Silicon: A Layer-by-Layer Assembly Approach Comparing Dip and Spin Coating", Int. J. Mol. Sci.., June, 2023. Vol. 24(13), pp. 10595. Multidisciplinary Digital Publishing Institute. |
| Abstract: The design and engineering of antibacterial materials are key for preventing bacterial adherence and proliferation in biomedical and household instruments. Silver nanoparticles (AgNPs) and chitosan (CHI) are broad-spectrum antibacterial materials with different properties whose combined application is currently under optimization. This study proposes the formation of antibacterial films with AgNPs embedded in carboxymethylcellulose/chitosan multilayers by the layer-by-layer (LbL) method. The films were deposited onto nanoporous silicon (nPSi), an ideal platform for bioengineering applications due to its biocompatibility, biodegradability, and bioresorbability. We focused on two alternative multilayer deposition processes: cyclic dip coating (CDC) and cyclic spin coating (CSC). The physicochemical properties of the films were the subject of microscopic, microstructural, and surfacetextendashinterface analyses. The antibacterial activity of each film was investigated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria strains as model microorganisms. According to the findings, the CDC technique produced multilayer films with higher antibacterial activity for both bacteria compared to the CSC method. Bacteria adhesion inhibition was observed from only three cycles. The developed AgNPstextendashmultilayer composite film offers advantageous antibacterial properties for biomedical applications. Keywords: antibacterial films; carboxymethylcellulose; chitosan; silver nanoparticles; nanoporous silicon; composite material; layer-by-layer |
BibTeX:
@article{Naveas2023MDPIIJMS13,
author = {Naveas, Nelson and Pulido, Ruth and Torres-Costa, Vicente and Agulló-Rueda, Fernando and Santibáñez, Mauricio and Malano, Francisco and Recio-Sánchez, Gonzalo and Garrido-Miranda, Karla A. and Manso-Silván, Miguel and Hernández-Montelongo, Jacobo},
title = {Antibacterial Films of Silver Nanoparticles Embedded into Carboxymethylcellulose/Chitosan Multilayers on Nanoporous Silicon: A Layer-by-Layer Assembly Approach Comparing Dip and Spin Coating},
journal = {Int. J. Mol. Sci.},
publisher = {Multidisciplinary Digital Publishing Institute},
year = {2023},
volume = {24},
number = {13},
pages = {10595},
url = {https://doi.org/10.3390/ijms241310595},
doi = {10.3390/ijms241310595}
}
|
| Fernandez Garcia A, Garcia-Lechuga M, Torres Costa V, de Melo Pereira O, Agulló-Rueda F and Manso Silvan M (2022), "Synthesis and laser modification of WTe_2-xSe_x via reduction and tellurization/selenization of WO_y grown by sol-gel", In E-MRS Spring Meeting, Virtual Conference, May 30--June 3, 2022. |
BibTeX:
@inproceedings{Fernandez-Garcia2022EMRSO,
author = {Fernandez Garcia, A. and Garcia-Lechuga, M. and Torres Costa, V. and de Melo Pereira, O. and Agulló-Rueda, F. and Manso Silvan, M.},
title = {Synthesis and laser modification of WTe_2-xSe_x via reduction and tellurization/selenization of WO_y grown by sol-gel},
booktitle = {E-MRS Spring Meeting, Virtual Conference, May 30--June 3, 2022},
year = {2022},
url = {https://www.european-mrs.com/nano-engineered-coatings-and-thin-films-design-applications-emrs-0}
}
|
| Garcia-Lechuga M, Solana I, Ynsa MD and Agulló-Rueda F (2022), "ABS: 205. Silicon amorphization studies by synergistic MeV proton implantation and femtosecond laser irradiation", In 22th International Conference on Ion Beam Modification of Materials (IBMM-2022), Lisbon, 10--15 July 2022. |
BibTeX:
@inproceedings{Garcia-Lechuga2022IBMM,
author = {Garcia-Lechuga, Mario and Solana, Irene and Ynsa, Maria Dolores and Agulló-Rueda, Fernando},
title = {ABS: 205. Silicon amorphization studies by synergistic MeV proton implantation and femtosecond laser irradiation},
booktitle = {22th International Conference on Ion Beam Modification of Materials (IBMM-2022), Lisbon, 10--15 July 2022},
year = {2022},
url = {http://www.ctn.tecnico.ulisboa.pt/IBMM-2022/}
}
|
| Pulido R, Naveas N, Martin-Palma RJ, Agulló-Rueda F, Ferró VR, Hernández-Montelongo J, Recio-Sánchez G, Brito I and Manso-Silván M (2022), "Phonon Structure, Infra-Red and Raman Spectra of Li_2MnO_3 by First-Principles Calculations", Materials., September, 2022. Vol. 15(18), pp. 6237. Multidisciplinary Digital Publishing Institute. |
| Abstract: The layer-structured monoclinic Li_2MnO_3 is a key material, mainly due to its role in Li-ion batteries and as a precursor for adsorbent used in lithium recovery from aqueous solutions. In the present work, we used first-principles calculations based on density functional theory (DFT) to study the crystal structure, optical phonon frequencies, infra-red (IR), and Raman active modes and compared the results with experimental data. First, Li_2MnO_3 powder was synthesized by the hydrothermal method and successively characterized by XRD, TEM, FTIR, and Raman spectroscopy. Secondly, by using Local Density Approximation (LDA), we carried out a DFT study of the crystal structure and electronic properties of Li_2MnO_3. Finally, we calculated the vibrational properties using Density Functional Perturbation Theory (DFPT). Our results show that simulated IR and Raman spectra agree well with the observed phonon structure. Additionally, the IR and Raman theoretical spectra show similar features compared to the experimental ones. This research is useful in investigations involving the physicochemical characterization of Li_2MnO_3 material. |
BibTeX:
@article{Pulido20220908MDPIMAT18,
author = {Pulido, Ruth and Naveas, Nelson and Martin-Palma, Raúl J. and Agulló-Rueda, Fernando and Ferró, Victor R. and Hernández-Montelongo, Jacobo and Recio-Sánchez, Gonzalo and Brito, Ivan and Manso-Silván, Miguel},
title = {Phonon Structure, Infra-Red and Raman Spectra of Li_2MnO_3 by First-Principles Calculations},
journal = {Materials},
publisher = {Multidisciplinary Digital Publishing Institute},
year = {2022},
volume = {15},
number = {18},
pages = {6237},
url = {https://doi.org/10.3390/ma15186237},
doi = {10.3390/ma15186237}
}
|
| de Melo O, Agulló-Rueda F and Torres-Costa V (2021), "Spatially resolved MoO_x phases by laser localized oxidation of MoO_2: A possible route for all-molybdenum-oxide devices", J. Mater. Chem. C., May, 2021. Vol. 9, pp. 6579-6588. The Royal Society of Chemistry. |
| Abstract: MoO_2 thin films were subjected to a laser localized oxidation process that allowed to obtain different well defined MoO_x phases. In particular, spatially resolved MoO_2, α-MoO_3, β-MoO_3, amorphous a-MoO_3, and Mo_4O_11 regions were obtained as a function of the laser power and the distance to the laser focus. The origin of this spatial phase separation was investigated through a careful and exhaustive Raman mapping study covering several micrometres away from the laser focus and taking into account the thermochemical properties of the species involved. It was found that a sublimation/deposition process, driven by the different vapour pressures of the species, was responsible for the phase separation. At higher laser power, a solid state reaction was observed to contribute as well. In the laser annealed tracks, distant lateral sidebands of oxide deposition were observed with composition that depended on the laser power and the distance to the centre of the track. Electrical measurements between irradiated and non-irradiated regions showed a strong rectifying behaviour, revealing a transformation from metal-like to semiconducting Mo oxide phases, which may open the way to the development of laser written all-oxide electronic circuits. |
BibTeX:
@article{deMelo2021JMCC04,
author = {de Melo, Osvaldo and Agulló-Rueda, Fernando and Torres-Costa, Vicente},
title = {Spatially resolved MoO_x phases by laser localized oxidation of MoO_2: A possible route for all-molybdenum-oxide devices},
journal = {J. Mater. Chem. C},
publisher = {The Royal Society of Chemistry},
year = {2021},
volume = {9},
pages = {6579--6588},
url = {https://doi.org/10.1039/D1TC00696G},
doi = {10.1039/D1TC00696G}
}
|
| Fernández Garc\ia A, Torres-Costa V, de Melo O, Agulló-Rueda F, Castro GR and Manso Silvan M (2021), "Growth of out-of-plane standing MoTe_2(1-x)Se_2x/MoSe_2 composite flake films by sol-gel nucleation of MoO_y and isothermal closed space telluro-selenization", Appl. Surf. Sci.., Jan, 2021. Vol. 546, pp. 149076. North-Holland. |
| Abstract: This study describes the sol-gel processing of MoO_y on Si (100) to subsequently achieve out-of-plane MoTe_2/MoSe_2 flake composite films by an isothermal closed space vapor transformation. The oxide precursor films have been prepared from a Mo isopropoxide solution in isopropanol and acid catalysis induced by HCl. Thermal annealing at 200, 400 and 600^circC enhanced the condensation after xerogel formation. An x-ray absorption analysis demonstrates that films condensed at 200^circC are at an intermediate chemical state between MoO_3 and MoO_2. To achieve MoTe_2/MoSe_2 composite films, the precursor oxide films were reduced in H_2 and exposed to the chalcogenides by isothermal closed space vapor transport at 600^circC. The multilayered nanocomposite films grow with an out-of-plane flake-like structure and an evident integration of Se in the MoTe_2 phase according to a MoTe_2(1-x)Se_2x alloy, with an estimation of x of 0.25. The alloy and the orientation of the flakes is consistent with the bands present in the Raman spectrum. These films are attractive for applications requiring high surface area interfaces favoring gas or ion exchange reactions with transition metal dichalcogenides. |
BibTeX:
@article{FernandezGarcia2021ASS01,
author = {Fernández Garc\ia, A. and Torres-Costa, V. and de Melo, O. and Agulló-Rueda, F. and Castro, G. R. and Manso Silvan, M.},
title = {Growth of out-of-plane standing MoTe_2(1-x)Se_2x/MoSe_2 composite flake films by sol-gel nucleation of MoO_y and isothermal closed space telluro-selenization},
journal = {Appl. Surf. Sci.},
publisher = {North-Holland},
year = {2021},
volume = {546},
pages = {149076},
url = {https://doi.org/10.1016/j.apsusc.2021.149076},
doi = {10.1016/j.apsusc.2021.149076}
}
|
| Pulido R, Naveas N, Graber T, Mart\in-Palma R, Agulló-Rueda F, Brito I, Morales C, Soriano L, Pascual L, Marini C, Hernández-Montelongo J and Manso Silván M (2021), "Hydrothermal control of the lithium-rich Li_2MnO_3 phase in lithium manganese oxide nanocomposites and their application as precursors for lithium adsorbents", Dalton Trans.. Vol. 50(31), pp. 10765-10778. |
| Abstract: Lithium manganese oxides (LMO) are key materials due to their role in Li-ion batteries and lithium recovery from aqueous lithium resources. In the present work, we investigated the effect of the crystallization temperature on the formation by hydrothermal synthesis of LMO nanocomposites with high Li/Mn ratios. It is demonstrated that LMO with a high Li/Mn ratio can be formed by systematically favoring the lithium-rich layered monoclinic phase (Li_2MnO_3) in a mixture of monoclinic and spinel crystalline phases. LMO nanocomposites have been characterized in terms of morphology, size, crystallinity, chemical composition and surface properties. Moreover, lithium adsorption experiments were conducted using acid-treated LMO (HMO) to evaluate the functionality of the nanocomposites as lithium adsorbent materials in LiCl buffer solution. This study spotlights in the structural, compositional, and functional properties of the different LMO nanocomposites obtained by the hydrothermal method using the same Li and Mn precursor compounds under slight variation crystallization temperatures. According to our knowledge, this is the first report of the successful application of lithium-rich Li_2MnO_3 phase in lithium manganese oxide nanocomposites as lithium adsorbent materials. With the recovered information, specific LMO nanocomposites with controlled amounts of the layered phase can be engineered to optimize lithium recovery from aqueous lithium resources. |
BibTeX:
@article{Pulido2021DT,
author = {Pulido, Ruth and Naveas, Nelson and Graber, Teófilo and Mart\in-Palma, Raúl and Agulló-Rueda, Fernando and Brito, Iván and Morales, Carlos and Soriano, Leonardo and Pascual, Laura and Marini, Carlo and Hernández-Montelongo, Jacobo and Manso Silván, Miguel},
title = {Hydrothermal control of the lithium-rich Li_2MnO_3 phase in lithium manganese oxide nanocomposites and their application as precursors for lithium adsorbents},
journal = {Dalton Trans.},
year = {2021},
volume = {50},
number = {31},
pages = {10765--10778},
url = {https://pubs.rsc.org/en/journals/journal/dt},
doi = {10.1039/D1DT01638E}
}
|
| Naveas N, Manso Silvan M, Pulido R, Agulló-Rueda F, Torres-Costa V, Plaza T, Pesenti H, Recio G and Hernandez-Montelongo J (2020), "Fabrication and characterization of nanostructured porous silicon-silver composite layers by cyclic deposition: dip-coating vs spin-coating", Nanotechnol.. Vol. 31, pp. 365704. |
| Abstract: Composites of nanostructured porous silicon and silver (nPSi-Ag) have attracted great attention due to the wide spectrum of applications in fields such as microelectronics, photonics, photocatalysis and bioengineering, Among the different methods for the fabrication of nanostructured composite materials, dip and spin-coating are simple, versatile, and cost-effective bottom-up technologies to provide functional coatings. In that sense, we aimed at fabricating nPSi-Ag composite layers. Using nPSi layers with pore diameter of 30 nm, two types of thin-film techniques were systematically compared: cyclic dip-coating (CDC) and cyclic spin-coating (CSC). CDC technique formed a mix of granular and flake-like structures of metallic Ag, and CSC method favored the synthesis of flake-like structures with Ag and Ag_2O phases. Flakes obtained by CDC and CSC presented a width of 110 nm and 70 nm, respectively. Particles also showed a nanostructure surface with features around 25 nm. According to the results of EDX and RBS, integration of Ag into nPSi was better achieved using the CDC technique. SERS peaks related to chitosan adsorbed on Ag nanostructures were enhanced, especially in the nPSi-Ag composite layers fabricated by CSC compared to CDC, which was confirmed by FTDT simulations. These results show that CDC and CSC produce different nPSi-Ag composite layers for potential applications in bioengineering and photonics. |
BibTeX:
@article{Naveas2020NT,
author = {Naveas, Nelson and Manso Silvan, Miguel and Pulido, Ruth and Agulló-Rueda, Fernando and Torres-Costa, Vicente and Plaza, Tanya and Pesenti, Hector and Recio, Gonzalo and Hernandez-Montelongo, Jacobo},
title = {Fabrication and characterization of nanostructured porous silicon-silver composite layers by cyclic deposition: dip-coating vs spin-coating},
journal = {Nanotechnol.},
year = {2020},
volume = {31},
pages = {365704},
url = {https://doi.org/10.1088/1361-6528/ab96e5},
doi = {10.1088/1361-6528/ab96e5}
}
|
| Landa-Cánovas AR, Santiso J, Agulló-Rueda F, Herrero P, Navarrete-Astorga E, Ochoa-Mart\inez E, Ramos-Barrado JR and Gabás M (2019), "Nanostructural changes upon substitutional Al doping in ZnO sputtered films", Ceram. Int.. Vol. 45(5), pp. 6319-6327. |
| Abstract: Al:ZnO layers, with low and high Al content, 0.2% and 2.1% cat. respectively, have been prepared using the RF magnetron sputtering technique. Noticeable differences in the optical and electrical properties have been detected in these films. With doping, the resistivity decreases and the band-gap increases. The alterations in the films crystalline structure are explained in terms of the nanostructural changes induced by Al substitutional doping, such as a higher concentration of edge dislocation defects and a higher rotation of crystalline nanodomains in the plane of the films (normal to the preferential orientation c-axis) for the high content Al:ZnO layer. A complete description of such effects has been accomplished using several characterization techniques, such as X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The combination of these techniques provides an exhaustive understanding of the films nanostructure. |
BibTeX:
@article{Landa-Canovas2019CI,
author = {Landa-Cánovas, A. R. and Santiso, J. and Agulló-Rueda, F. and Herrero, P. and Navarrete-Astorga, E. and Ochoa-Mart\inez, E. and Ramos-Barrado, J. R. and Gabás, M.},
title = {Nanostructural changes upon substitutional Al doping in ZnO sputtered films},
journal = {Ceram. Int.},
year = {2019},
volume = {45},
number = {5},
pages = {6319--6327},
url = {https://doi.org/10.1016/j.ceramint.2018.12.116},
doi = {10.1016/j.ceramint.2018.12.116}
}
|
| Pellacani P, Torres-Costa V, Agulló-Rueda F, Vanna R, Morasso C and Manso Silván M (2019), "Laser writing of nanostructured silicon arrays for the SERS detection of biomolecules with inhibited oxidation", Colloids Surf., B. Vol. 174, pp. 174-180. |
| Abstract: The present work reports the processing of laser irradiated Si arrays (LISi) and underlines their surface enhanced Raman scattering (SERS) functionality. A nanostructured Si/SiOx surface forms providing additional fluidic and photoprotective properties. Because of their optical and surface characteristics, the arrays exhibit a SERS analytical enhancing factor of 500, without any noble metals such as gold or silver. Micro-Raman maps allowed studying LISi properties, identifying maximum amplification in nanostructured areas characterized by the presence of 7 nm Si nanocrystals. These structures are confined by a SiOx layer as illustrated by XPS valence band measurements. The highly hydrophilic LISi areas allow a pre-concentration of target molecules prior to SERS analysis. A relevant application of LISi was found in the detection of apomorphine (APO), a drug used for the treatment of Parkinson’s disease. In contrast with what is obtained by using gold SERS substrates, LISi allows the detection of APO with no sign of oxidation. This invites for the use of the Si/SiOx SERS detection in future systems for the personalized delivery of APO. |
BibTeX:
@article{Pellacani2019COLSURF,
author = {Pellacani, P. and Torres-Costa, V. and Agulló-Rueda, F. and Vanna, R. and Morasso, C. and Manso Silván, M.},
title = {Laser writing of nanostructured silicon arrays for the SERS detection of biomolecules with inhibited oxidation},
journal = {Colloids Surf., B},
year = {2019},
volume = {174},
pages = {174--180},
url = {https://doi.org/10.1016/j.colsurfb.2018.11.010},
doi = {10.1016/j.colsurfb.2018.11.010}
}
|
| Agulló-Rueda F and Serna R (2018), "Propiedades ópticas", In Capas delgadas y modificación superficial de materiales. Consejo Superior de Investigaciones Cient\ificas. |
| Abstract: Los métodos ópticos de caracterización han sido desde el principio fundamentales en el estudio de la materia, el desarrollo de la astronomía y de la teoría cuántica. Estos métodos son en general no destructivos y relativamente económicos, pues en el caso más sencillo basta dirigir un haz de luz sobre la muestra y estudiar su respuesta óptica. En el caso de las capas delgadas, la información obtenida es muy amplia y no sólo se limita a las propiedades ópticas, ya que también se puede obtener el espesor de las muestras, su rugosidad, composición química, defectos e incluso la estructura atómica y electrónica. En la primera parte de este capítulo se repasan los fundamentos de la interacción luz-materia. En la segunda parte se introducen los metódos ópticos y espectroscópicos de análisis más relevantes (reflectancia, transmitancia, elipsometría, fluorescencia y espectroscopías vibracionales) y su aplicación a capas delgadas. |
BibTeX:
@incollection{Agullo-Rueda2018CH,
author = {Agulló-Rueda, F. and Serna, R.},
editor = {Albella Mart\in, José Mar\ia},
title = {Propiedades ópticas},
booktitle = {Capas delgadas y modificación superficial de materiales},
publisher = {Consejo Superior de Investigaciones Cient\ificas},
year = {2018},
url = {http://editorial.csic.es/publicaciones/libros/13119/978-84-00-10438-2/capas-delgadas-y-modificacion-superficial-de-mater.html}
}
|
| Canca J, Hernández-Velasco J, Landa-Cánovas A and Agulló-Rueda F (2018), "FeSbO_4 and other rutile-type mixed oxides revealing nano-structural flexibility", Acta Crystallogr., Sect. A: Found. Adv.., In 31st European Crystallographic Meeting, Oviedo, Spain 22--27 August., Aug, 2018. Vol. 74, pp. e327. International Union of Crystallography. |
BibTeX:
@inproceedings{Canca2018ACR,
author = {Canca, J. and Hernández-Velasco, J. and Landa-Cánovas, A. and Agulló-Rueda, F.},
title = {FeSbO_4 and other rutile-type mixed oxides revealing nano-structural flexibility},
booktitle = {31st European Crystallographic Meeting, Oviedo, Spain 22--27 August},
journal = {Acta Crystallogr., Sect. A: Found. Adv.},
publisher = {International Union of Crystallography},
year = {2018},
volume = {74},
pages = {e327},
url = {https://doi.org/10.1107/S2053273318090290},
doi = {10.1107/S2053273318090290}
}
|
| Serna R and Agulló-Rueda F (2018), "Aplicaciones ópticas de láminas delgadas", In Capas delgadas y modificación superficial de materiales. Consejo Superior de Investigaciones Cient\ificas. |
| Abstract: En los últimos años se ha conseguido un gran avance en la tecnología de capas delgadas para aplicaciones ópticas. Esto es debido a que las aplicaciones tecnológicas han ido aumentado el nivel de exigencia en lo que se refiere a la calidad y prestaciones de las capas delgadas. Es interesante reseñar que ha sido el uso de las láminas delgadas tanto en sectores cotidianos, p.e. el de la construcción y la automoción, como en sectores mas tecnológicos. Entre ellos cabe citar la óptica integrada, láseres, telecomunicaciones por fibra, sensores, aplicaciones espaciales y militares, los cuales han llevado este campo a un constante desarrollo. En este siglo XXI es de esperar que las nuevas necesidades de la sociedad impondrán aún nuevos retos. En este capítulo se repasanlas propiedades ópticas de los sistemas formados por múltiples capas delgadas, discutiendo algunas de las aplicaciones mas comunes. |
BibTeX:
@incollection{Serna2018CH,
author = {Serna, R. and Agulló-Rueda, F.},
editor = {Albella Mart\in, José Mar\ia},
title = {Aplicaciones ópticas de láminas delgadas},
booktitle = {Capas delgadas y modificación superficial de materiales},
publisher = {Consejo Superior de Investigaciones Cient\ificas},
year = {2018},
url = {http://editorial.csic.es/publicaciones/libros/13119/978-84-00-10438-2/capas-delgadas-y-modificacion-superficial-de-mater.html}
}
|
| Agulló-Rueda F, Gordillo N, Ynsa MD, Maira A, Cañas J and Ramos MA (2017), "Lattice damage in 9-MeV-carbon irradiated diamond and its recovery after annealing", Carbon. Vol. 123, pp. 334-343. |
| Abstract: We have studied the radiation damage in diamond as a function of layer depth upon self-ion implantation with 9-MeV carbon ions and its recovery after annealing at 1000^circC. Raman and photoluminescence spectra show substantial damage of the lattice, namely, amorphization, neutral vacancies, and interstitial defects. Damage is maximum in the stopping layer at a depth of 4 μm. After annealing there is some recovery of the lattice, but the residual damage increases with fluence, up to about 2 × 10^16 ions/cm^2. At this fluence the stopping layer becomes highly disordered and does not heal with annealing. Surprisingly, for higher fluence values, of about 5 × 10^16 ions/cm^2, there is almost no residual damage. After full amorphization is reached, the layers appear to recrystallize by solid phase epitaxy (SPE), using the pristine diamond layers underneath as a template. These results prove that graphitization of diamond after annealing can be avoided in deeply buried layers, implanted at fluences much higher than expected. High fluences, in fact, can lead to high quality diamond layers. If SPE can be confirmed, it would have a great interest for diamond device applications, as it allows for higher doping levels. |
BibTeX:
@article{Agullo-Rueda2017CRB,
author = {F. Agulló-Rueda and N. Gordillo and M. D. Ynsa and A. Maira and J. Cañas and M. A. Ramos},
title = {Lattice damage in 9-MeV-carbon irradiated diamond and its recovery after annealing},
journal = {Carbon},
year = {2017},
volume = {123},
pages = {334--343},
url = {http://dx.doi.org/10.1016/j.carbon.2017.07.076},
doi = {10.1016/j.carbon.2017.07.076}
}
|
| Agulló-Rueda F, Ynsa MD, Gordillo N, Maira A, Moreno-Cerrada D and Ramos MA (2017), "Micro-Raman spectroscopy of near-surface damage in diamond irradiated with 9-MeV boron ions", Diamond Relat. Mater.. Vol. 72, pp. 94-98. |
| Abstract: We have studied the near-surface damage in a diamond crystal caused by irradiation with swift boron ions and its healing after high-temperature annealing. A diamond crystal was irradiated with 9-MeV ^11B^3+ ions with fluence values between 1 × 10^15 and 4.42 × 10^16 ions/cm^2 to generate various levels of lattice damage. The ions loose energy to the lattice and, according to simulations, stop at a depth of about 5 μm, where they form a thin buried implantation layer. For the near-surface layers damage is produced by the ions at high kinetic energy before they slow down. Only intrinsic defects can be produced, with no boron atoms. The lattice damage of the near-surface layers and its recovery after annealing for 1 h at 1000^C were studied by Raman and photoluminescence spectroscopies. Back-scattered light from a 514.5-nm laser beam was collected from the sample surface, probing a depth of a few micrometers. We observe some disordering of the lattice plus the formation of neutral vacancies, interstitial and other lattice defects. After annealing the Raman spectrum shows a significant recovery of the lattice order and the disappearance of isolated neutral vacancies. Residual damage is confirmed by the luminescence spectrum, that shows the appearance of new spectral features. |
BibTeX:
@article{Agullo-Rueda2017DRM,
author = {F. Agulló-Rueda and M. D. Ynsa and N. Gordillo and A. Maira and D. Moreno-Cerrada and M. A. Ramos},
title = {Micro-Raman spectroscopy of near-surface damage in diamond irradiated with 9-MeV boron ions},
journal = {Diamond Relat. Mater.},
year = {2017},
volume = {72},
pages = {94--98},
url = {http://dx.doi.org/10.1016/j.diamond.2017.01.010},
doi = {10.1016/j.diamond.2017.01.010}
}
|
| Gabás M, Ochoa-Mart\inez E, Navarrete-Astorga E, Landa-Cánovas AR, Herrero P, Agulló-Rueda F, Palanco S, Mart\inez-Serrano JJ and Ramos-Barrado JR (2017), "Characterization of the interface between highly conductive Ga:ZnO films and the silicon substrate", Appl. Surf. Sci.. Vol. 419, pp. 595-602. |
| Abstract: Gallium-doped zinc oxide films are an interesting alternative for transparent conductive materials. To improve their performance, the interface between the grown layer and the substrate must be fully understood. Accordingly, ZnO and Ga:ZnO films have been deposited onto p-type doped Si (111) substrates by magnetron sputtering for 1, 2, 3 and 20 min and their interfaces characterized by transmission electron microscopy, photoelectron spectroscopy, spectroscopic ellipsometry and impedance spectroscopy. The combination of transmission electron microscopy techniques suggested a more complex interface chemistry in the Ga:ZnO/Si case, a point confirmed by x-ray photoelectron spectroscopy measurements on very thin films. While the ZnO/Si interface consists mostly of silicon oxides, zinc silicates and some Zn^0, the Ga:ZnO/Si interface, besides these constituents, has a noticeable amount of Ga:ZnO and small quantities of Ga^0. The band alignment deduced from the photoelectron spectroscopy measurements, together with the layers and Si band gap values, evidences a higher work function for the doped film and a smaller conduction band barrier for the Ga:ZnO/Si interface. Concerning the optical and electrical characteristics, spectroscopic ellipsometry revealed no significant differences between the two interfaces, while impedance spectroscopy measurements demonstrated that the Ga:ZnO/Si interface is less resistive than the ZnO/Si one. |
BibTeX:
@article{Gabas2017ASS,
author = {Gabás, M. and Ochoa-Mart\inez, E. and Navarrete-Astorga, E. and Landa-Cánovas, A. R. and Herrero, P. and Agulló-Rueda, F. and Palanco, S. and Mart\inez-Serrano, J. J. and Ramos-Barrado, J. R.},
title = {Characterization of the interface between highly conductive Ga:ZnO films and the silicon substrate},
journal = {Appl. Surf. Sci.},
year = {2017},
volume = {419},
pages = {595--602},
url = {http://dx.doi.org/10.1016/j.apsusc.2017.05.072},
doi = {10.1016/j.apsusc.2017.05.072}
}
|
| Hernández-Velasco J, Canca-Ruiz J, Vilanova P, Puente-Orench I, Hoser A, Agulló-Rueda F and Landa-Cánovas AR (2017), "Incommensurate magnetic structure and chemical modulation in SbVO_4 catalyst", Acta Crystallogr. A.., Aug, 2017. Vol. 73(a2), pp. C373. |
BibTeX:
@article{Hernandez-Velasco2017ACA,
author = {Hernández-Velasco, Jorge and Canca-Ruiz, Jon and Vilanova, Paloma and Puente-Orench, Inés and Hoser, Andreas and Agulló-Rueda, Fernando and Landa-Cánovas, Angel R.},
title = {Incommensurate magnetic structure and chemical modulation in SbVO_4 catalyst},
journal = {Acta Crystallogr. A.},
year = {2017},
volume = {73},
number = {a2},
pages = {C373},
url = {https://doi.org/10.1107/S2053273317092002},
doi = {10.1107/S2053273317092002}
}
|
| Punzón-Quijorna E, Kajari-Shröder S, Agulló-Rueda F, Manso Silván M, Mart\in-Palma RJ, Herrero Fernández P, Torres-Costa V and Climent-Font A (2017), "Study of the formation mechanism of hierarchical silicon structures produced by sequential ion beam irradiation and anodic etching", Vacuum. Vol. 138, pp. 238-243. |
| Abstract: The formation of micropatterns combining nanostructured (porous) Si (NPSi) and bulk Si is induced by a sequential process of selective high energy ion irradiation and anodic etching. In this work, we investigate the microstructural origin of the increase of Si resistivity on irradiated areas, which is responsible for the inhibition of NPSi formation upon anodization. The increase of Si resistivity after irradiation at variable fluence has been evidenced from current voltage (I-V) characteristics. Microstructural aspects of the Si interfaces irradiated with 1.5--20 MeV Si ions have been revealed by elastic backscattering experiments in channeling configuration, Raman spectroscopy and high resolution transmission electron microscopy. It is concluded that inhibition of NPSi formation is induced at fluences that do not imply amorphization. In fact, the analysis of electrochemical capacitance-voltage measurements suggests that, at fluences well below the threshold for lattice disruption, the concentration of holes suffers from a drastic decrease at depths that match the location of maximum damage yield of the implanted Si ions. These results suggest that the mechanism responsible of formation of hierarchical Si structures is the local B dopant deactivation in the irradiated areas. |
BibTeX:
@article{Punzon-Quijorna2017VAC,
author = {Punzón-Quijorna, Esther and Kajari-Shröder, Sarah and Agulló-Rueda, Fernando and Manso Silván, Miguel and Mart\in-Palma, Raul José and Herrero Fernández, Pilar and Torres-Costa, Vicente and Climent-Font, Aurelio},
title = {Study of the formation mechanism of hierarchical silicon structures produced by sequential ion beam irradiation and anodic etching},
journal = {Vacuum},
year = {2017},
volume = {138},
pages = {238--243},
url = {http://dx.doi.org/10.1016/j.vacuum.2016.10.011},
doi = {10.1016/j.vacuum.2016.10.011}
}
|
| Ynsa MD, Agulló-Rueda F, Gordillo N, Maira A, Moreno-Cerrada D and Ramos MA (2017), "Study of the effects of focused high-energy boron ion implantation in diamond", Nucl. Instrum. Methods Phys. Res., Sect. B. Vol. 404, pp. 207-210. |
| Abstract: Boron-doped diamond is a material with a great technological and industrial interest because of its exceptional chemical, physical and structural properties. At modest boron concentrations, insulating diamond becomes a p-type semiconductor and at higher concentrations a superconducting metal at low temperature. The most conventional preparation method used so far, has been the homogeneous incorporation of boron doping during the diamond synthesis carried out either with high-pressure sintering of crystals or by chemical vapour deposition (CVD) of films. With these methods, high boron concentration can be included without distorting significantly the diamond crystalline lattice. However, it is complicated to manufacture boron-doped microstructures. A promising alternative to produce such microstructures could be the implantation of focused high-energy boron ions, although boron fluences are limited by the damage produced in diamond. In this work, the effect of focused high-energy boron ion implantation in single crystals of diamond is studied under different irradiation fluences and conditions. Micro-Raman spectra of the sample were measured before and after annealing at 1000^circC as a function of irradiation fluence, for both superficial and buried boron implantation, to assess the changes in the diamond lattice by the creation of vacancies and defects and their degree of recovery after annealing. |
BibTeX:
@article{Ynsa2017NIMPRB,
author = {Ynsa, M. D. and Agulló-Rueda, F. and Gordillo, N. and Maira, A. and Moreno-Cerrada, D. and Ramos, M. A.},
title = {Study of the effects of focused high-energy boron ion implantation in diamond},
journal = {Nucl. Instrum. Methods Phys. Res., Sect. B},
year = {2017},
volume = {404},
pages = {207--210},
url = {https://doi.org/10.1016/j.nimb.2017.01.052},
doi = {10.1016/j.nimb.2017.01.052}
}
|
| Perea GB, Solanas C, Mar\i-Buyé N, Madurga R, Agulló-Rueda F, Muinelo A, Riekel C, Burghammer M, Jorge I, Vázquez J, Plaza GR, Torres AL, del Pozo F, Guinea GV, Elices M, Cenis JL and Pérez-Rigueiro J (2016), "The apparent variability of silkworm (Bombyx mori) silk and its relationship with degumming", Eur. Polym. J.., May, 2016. Vol. 78, pp. 129-140. |
| Abstract: As spun silkworm (Bombyx mori) silk fibers were compared in terms of their tensile behavior and microstructure with fibers subjected to different degumming treatments. Fibers were initially retrieved by forced silking directly from the worms and, either characterized in the as spun condition, or subjected to one of the following treatments: immersion in water, conventional degumming or degumming under longitudinally constrained conditions. Microstructure was assessed by X-ray diffraction and Raman spectroscopy. In addition, polyacrylamide gel electrophoresis was used to determine the influence of degumming on silk at a molecular level. Our study not only shows that degumming represents a major contribution to the accepted idea of silkworm silk as a highly variable material, but also provides new insights in the relationship between microstructure and tensile behavior in these fibers. In particular, it is shown that the arrangement of the hydrogen bond network in fibers subjected to different treatments plays a critical role in determining the mechanical behavior of silkworm silk. |
BibTeX:
@article{Perea2016EPJ,
author = {Perea, Gracia Belén and Solanas, Concepción and Mar\i-Buyé, Núria and Madurga, Rodrigo and Agulló-Rueda, Fernando and Muinelo, Alfonso and Riekel, Christian and Burghammer, Manfred and Jorge, Inmaculada and Vázquez, Jesús and Plaza, Gustavo R. and Torres, Adriana L. and del Pozo, Francisco and Guinea, Gustavo V. and Elices, Manuel and Cenis, José Luis and Pérez-Rigueiro, José},
title = {The apparent variability of silkworm (Bombyx mori) silk and its relationship with degumming},
journal = {Eur. Polym. J.},
year = {2016},
volume = {78},
pages = {129--140},
url = {http://dx.doi.org/10.1016/j.eurpolymj.2016.03.012},
doi = {10.1016/j.eurpolymj.2016.03.012}
}
|
| Vilanova-Mart\inez P, Hernández-Velasco J, Landa-Cánovas AR and Agulló-Rueda F (2016), "Laser heating induced phase changes of VO_2 crystals in air monitored by Raman spectroscopy", J. Alloys Compd.. Vol. 661, pp. 122-125. |
BibTeX:
@article{Vilanova-Martinez2016JAC,
author = {P. Vilanova-Mart\inez and J. Hernández-Velasco and A. R. Landa-Cánovas and F. Agulló-Rueda},
title = {Laser heating induced phase changes of VO_2 crystals in air monitored by Raman spectroscopy},
journal = {J. Alloys Compd.},
year = {2016},
volume = {661},
pages = {122--125},
url = {http://dx.doi.org/10.1016/j.jallcom.2015.11.174},
doi = {10.1016/j.jallcom.2015.11.174}
}
|
| Xiang Y, Mart\inez Mart\inez R, Torres-Costa V, Agulló-Rueda F, Garc\ia-Ruiz JP and Manso Silván M (2016), "Direct laser writing of nanorough cell microbarriers on anatase/Si and graphite/Si", Mater. Sci. Eng. C. Vol. 66, pp. 8-15. |
| Abstract: The formation of hierarchical structures consisting of microstripe barriers decorated with nanorough ablated materials prepared by direct laser writing is described. Linear features of circa 25 μm width and 12 μm height are achieved on amorphous and crystalline titania and graphitic carbon films deposited on silicon. Ablated protrusions build up barriers decorated by nanoscale Si-film reconstructions, as indicated by EDX maps and micro-Raman spectroscopy. Wettability tests show a dramatic change in water contact angle, which leads to almost full wetting after irradiation, irrespective of the original film composition. Fluorescence microscopy images of human mesenchymal stem cells cultured on 1D and 2D structures demonstrate the short term biocompatibility of the ablated surfaces. It is shown that cells adhere, extend and polarize on feature edges, independently of the type of surface, thus suggesting that the created nanoroughness is at the origin of the antifouling behavior. In particular, irradiated anatase and graphite surfaces demonstrate an increased performance of crystalline films for the creation of cell guiding and trapping devices. The results suggest that such laser processing of films may serve as a time-and-cost-efficient method for the design of few-cells analytical surfaces. |
BibTeX:
@article{Xiang2016MSEC,
author = {Xiang, Yuchen and Mart\inez Mart\inez, Rosa and Torres-Costa, Vicente and Agulló-Rueda, Fernando and Garc\ia-Ruiz, Josefa Predestinación and Manso Silván, Miguel},
title = {Direct laser writing of nanorough cell microbarriers on anatase/Si and graphite/Si},
journal = {Mater. Sci. Eng. C},
year = {2016},
volume = {66},
pages = {8--15},
url = {http://dx.doi.org/10.1016/j.msec.2016.04.059},
doi = {10.1016/j.msec.2016.04.059}
}
|
| Gabás M, Landa-Cánovas A, Costa-Krämer JL, Agulló-Rueda F, González-Elipe AR, D\iaz-Carrasco P, Hernández-Moro J, Lorite I, Herrero P, Castillero P, Barranco A and Ramos-Barrado JR (2013), "Differences in n-type doping efficiency between Al- and Ga-ZnO films", J. Appl. Phys.. Vol. 113(16), pp. 163709. |
| Abstract: A careful and wide comparison between Al and Ga as substitutional dopants in the ZnO wurtzite structure is presented. Both cations behave as n-type dopants and their inclusion improves the optical and electrical properties of the ZnO matrix, making it more transparent in the visible range and rising up its electrical conductivity. However, the same dopant/Zn ratio leads to a very different doping efficiency when comparing Al and Ga, being the Ga cation a more effective dopant of the ZnO film. The measured differences between Al- and Ga-doped films are explained with the hypothesis that different quantities of these dopant cations are able to enter substitutionally in the ZnO matrix. Ga cations seem to behave as perfect substitutional dopants, while Al cation might occupy either substitutional or interstitial sites. Moreover, the subsequent charge balance after doping appear to be related with the formation of different intrinsic defects that depends on the dopant cation. The knowledge of the doped-ZnO films microstructure is a crucial step to optimize the deposition of transparent conducting electrodes for solar cells, displays, and other photoelectronic devices. |
BibTeX:
@article{Gabas2013JAP,
author = {Gabás, M. and Landa-Cánovas, A. and Costa-Krämer, J. L. and Agulló-Rueda, F. and González-Elipe, A. R. and D\iaz-Carrasco, P. and Hernández-Moro, J. and Lorite, I. and Herrero, P. and Castillero, P. and Barranco, A. and Ramos-Barrado, J. R.},
title = {Differences in n-type doping efficiency between Al- and Ga-ZnO films},
journal = {J. Appl. Phys.},
year = {2013},
volume = {113},
number = {16},
pages = {163709},
url = {http://dx.doi.org/10.1063/1.4803063},
doi = {10.1063/1.4803063}
}
|
| Gago R, Vázquez L, Palomares FJ, Agulló-Rueda F, Vinnichenko M, Carcelén V, Olvera J, Plaza JL and Diéguez E (2013), "Self-organized surface nanopatterns on Cd(Zn)Te crystals induced by medium-energy ion beam sputtering", J. Phys. D. Vol. 46(45), pp. 455302. |
| Abstract: Cadmium telluride (CT) and Zn-doped (≈ 4 at CT (CZT) crystals grown by the Bridgman method were mechanically polished to achieve mirror-like surfaces and subsequently irradiated with medium-energy (30--200 keV) Ar^+ ions under oblique incidence (60^circ with respect to the target normal). Atomic force microscopy shows that ion sputtering induces the formation of self-organized ripple nanopatterns with wavevector parallel to the ion beam projection on the surface on both CT and CZT targets. The ripple wavelength and amplitude (surface roughness) increase with ion energy. Even with such low doping level, the pattern formation dynamics differs between both materials and, in general, CZT surfaces roughen more easily than CT. In addition, an orthogonal ripple mode develops for extended irradiation, which is more prominent in CZT crystals. Spectroscopic ellipsometry reveals that the C(Z)T crystals have a high radiation hardness since ion bombardment does not induce an amorphized surface layer. This fact also implies that the nanostructured surfaces have significant photoluminescence response, one to two orders of magnitude larger than from as-prepared crystals. These results show that large-area (≈ cm^2) surface nanostructuring by ion beams can be implemented in the fabrication of future C(Z)T-based devices. |
BibTeX:
@article{Gago2013JPD,
author = {R. Gago and L. Vázquez and F. J. Palomares and F. Agulló-Rueda and M. Vinnichenko and V. Carcelén and J. Olvera and J. L. Plaza and E. Diéguez},
title = {Self-organized surface nanopatterns on Cd(Zn)Te crystals induced by medium-energy ion beam sputtering},
journal = {J. Phys. D},
year = {2013},
volume = {46},
number = {45},
pages = {455302},
url = {http://dx.doi.org/10.1088/0022-3727/46/45/455302},
doi = {10.1088/0022-3727/46/45/455302}
}
|
| Gutiérrez-Neira PC, Agulló-Rueda F, Climent-Font A and Garrido C (2013), "Raman spectroscopy analysis of pigments on Diego Velázquez paintings", Vibrat. Spectrosc.. Vol. 69, pp. 13-20. |
| Abstract: Raman micro-spectroscopy has been used for the identification of the pigments used by the Spanish painter Diego Velázquez (1599--1650), considered one of the greatest painters in art history. The set of cross-sectional samples studied belongs to paintings of the Museo del Prado collection and correspond to the three known periods of the artist's activity. We have obtained information on the chemical composition and crystal structure of the pigments used for various colours. The results are consistent with previous elemental composition determined by other analytical methods. |
BibTeX:
@article{Gutierrez2013VBSP,
author = {Gutiérrez-Neira, P. C. and Agulló-Rueda, F. and Climent-Font, A. and Garrido, C.},
title = {Raman spectroscopy analysis of pigments on Diego Velázquez paintings},
journal = {Vibrat. Spectrosc.},
year = {2013},
volume = {69},
pages = {13--20},
url = {http://dx.doi.org/10.1016/j.vibspec.2013.09.007},
doi = {10.1016/j.vibspec.2013.09.007}
}
|
| Guinea GV, Elices M, Plaza GR, Perea GB, Daza R, Riekel C, Agulló-Rueda F, Hayashi C, Zhao Y and Pérez-Rigueiro J (2012), "Minor Ampullate Silks from Nephila and Argiope Spiders: Tensile Properties and Microstructural Characterization", Biomacromolecules., July, 2012. Vol. 13(7), pp. 2087-2098. |
| Abstract: The mechanical behavior and microstructure of minor ampullate gland silk (miS) of two orb-web spinning species, Argiope trifasciata and Nephila inaurata, were extensively characterized, enabling detailed comparison with other silks. The similarities and differences exhibited by miS when compared with the intensively studied major ampullate gland silk (MAS) and silkworm (Bombyx mori) silk offer a genuine opportunity for testing some of the hypotheses proposed to correlate microstructure and tensile properties in silk. In this work, we show that miSs of different species show similar properties, even when fibers spun by spiders that diverged over 100 million years are compared. The tensile properties of miS are comparable to those of MAS when tested in air, significantly in terms of work to fracture, but differ considerably when tested in water. In particular, miS does not show a supercontraction effect and an associated ground state. In this regard, the behavior of miS in water is similar to that of B. mori silk, and it is shown that the initial elastic modulus of both fibers can be explained using a common model. Intriguingly, the microstructural parameters measured in miS are comparable to those of MAS and considerably different from those found in B. mori. This fact suggests that some critical microstructural information is still missing in our description of silks, and our results suggest that the hydrophilicity of the lateral groups or the large scale organization of the sequences might be routes worth exploring. |
BibTeX:
@article{Guinea2012BMM,
author = {Guinea, G. V. and Elices, M. and Plaza, G. R. and Perea, G. B. and Daza, R. and Riekel, C. and Agulló-Rueda, F. and Hayashi, C. and Zhao, Y. and Pérez-Rigueiro, J.},
title = {Minor Ampullate Silks from Nephila and Argiope Spiders: Tensile Properties and Microstructural Characterization},
journal = {Biomacromolecules},
year = {2012},
volume = {13},
number = {7},
pages = {2087--2098},
url = {http://dx.doi.org/10.1021/bm3004644},
doi = {10.1021/bm3004644}
}
|
| Herrero-Fernández P, Hernández-Moro J, Agulló-Rueda F, Gabás M, D\iaz-Carrasco P, Ramos-Barrado JR and Landa-Cánovas AR (2012), "Nanostructure of the Interfaces Between ZnO, ZnO:Ga and ZnO:Al Films and Silicon", Microsc. Microanal.. Vol. 18(Supplement S5), pp. 91-92. |
| Abstract: ZnO is a promising material for use in solar cell applications which require antireflective coatings and transparent conducting materials in front contacts. Its resistivity can be reduced by appropriate doping with different group III elements, which act as donors, without sacrificing optical transmission. Besides, it constitutes a non-toxic and cheap alternative to ITO (In_2O_3:SnO_2), which is nowadays commonly used as transparent conducting oxide (TCO) in optoelectronic devices. Al(III) is one of the cheapest elements on nature, and has been therefore one of the first candidates to be used as a dopant. However recent studies demonstrate that for similar amounts of dopant the use of Ga largely improves both the optical and electrical properties of the films. The interface between Si (used as substrate) and the corresponding TCO is a critical part of Si-based solar cells, since the conversion efficiency may be profoundly altered by the presence of recombination centers formed at the interface. In this work we present a comparison of Si/ZnO, Si/ZnO:Ga and Si/ZnO:Al interfaces (with [dopant]/[Zn] = 2 by using HRTEM and associated spectroscopies. Resistivity values of the films are: ρ(ZnO) = 4.4 × 10^-2 Ω cm; ρ(Ga:ZnO) = 6.3 × 10^-4 Ω cm; ρ(Al:ZnO) = 2.9 × 10^-3 Ω cm. and the films optical transmitance is larger than 80% along the visible spectrum. |
BibTeX:
@article{HerreroFernandez2012MMANAL,
author = {Herrero-Fernández, P. and Hernández-Moro, J. and Agulló-Rueda, F. and Gabás, M. and D\iaz-Carrasco, P. and Ramos-Barrado, J. R. and Landa-Cánovas, A. R.},
title = {Nanostructure of the Interfaces Between ZnO, ZnO:Ga and ZnO:Al Films and Silicon},
journal = {Microsc. Microanal.},
year = {2012},
volume = {18},
number = {Supplement S5},
pages = {91--92},
url = {http://dx.doi.org/10.1017/S1431927612013116},
doi = {10.1017/S1431927612013116}
}
|
| Ochoa E, Gabás M, Bijani S, Palanco S, Landa-Cánovas AR, Herrero P, Agulló-Rueda F, D\iaz-Carrasco P and Ramos-Barrado JR (2012), "Highly conductive Ga-doped ZnO thin films deposited onto Si wafers: Interface characterization", In Photovoltaic Specialists Conference (PVSC), 2012 38th IEEE. , pp. 427-431. |
| Abstract: Undoped ZnO and Ga:ZnO films deposited onto Si wafer substrates have been prepared and characterized in order to investigate the suitability of Ga:ZnO as a transparent and conductive material. A comparative study between ZnO and Ga:ZnO properties using a wide variety of experimental techniques has been carried out. Our results prove the improvement of electrical and optical properties of Ga:ZnO films with respect to an undoped ZnO one. The interface between the film and the Si substrate has been explored in order to detect specific problems that could hinder an optimum electric contact between them. A very thin and abrupt Si/ZnO interface is observed using different characterization techniques, independently of doping. In spite of a dopant enrichment at the interface, the ZnO electronic band structure seems to smoothly adapt to the Si one. |
BibTeX:
@inproceedings{Ochoa2012PVSC12,
author = {Ochoa, E. and Gabás, M. and Bijani, S. and Palanco, S. and Landa-Cánovas, A. R. and Herrero, P. and Agulló-Rueda, F. and D\iaz-Carrasco, P. and Ramos-Barrado, J. R.},
title = {Highly conductive Ga-doped ZnO thin films deposited onto Si wafers: Interface characterization},
booktitle = {Photovoltaic Specialists Conference (PVSC), 2012 38th IEEE},
year = {2012},
pages = {427--431},
note = {Texas, June 3--8, 2012},
url = {http://dx.doi.org/10.1109/PVSC.2012.6317650},
doi = {10.1109/PVSC.2012.6317650}
}
|
| Plaza GR, Pérez-Rigueiro J, Riekel C, Perea GB, Agulló-Rueda F, Burghammer M, Elices M and Guinea GV (2012), "Relationship between microstructure and mechanical properties in spider silk fibers: two regimes in the microstructural changes", Soft Matter. Vol. 8(22), pp. 6015-6026. |
| Abstract: The relationship between microstructure and mechanical properties has been investigated in Argiope trifasciata dragline silk fibers (major ampullate silk, MAS) by X-ray diffraction, Raman spectroscopy and tensile testing. We have analyzed three fractions of the material, i.e. amorphous, highly oriented nanocrystals and weakly oriented material, for different values of the macroscopic alignment parameter α, calculated as the relative difference between the length of the fiber and its length when supercontracted. Two distinct regimes have been identified: for low values of the alignment parameter α, microstructural changes are dominated by the reorientation of the nanocrystals; however, at high values (α > 0.5) of the alignment parameter, an increase in the fraction of the crystalline phase is revealed. The two regimes are also reflected in the mechanical behaviour, which can be explained by microstructural changes. This finding of the two distinct regimes in the microstructural evolution, which separates the reorientation and the increase in the crystalline phase, will be valuable to develop and validate molecular models of natural and artificial silk fibers, as well as to deepen our present knowledge of the origin of the outstanding properties of MAS fibers. In addition, we have analyzed the characteristics of the crystal lattice, and discussed the relationship between the percentage of short side-chain residues and the unit cell dimensions in different silks. |
BibTeX:
@article{Plaza2012ALPHA,
author = {Gustavo R. Plaza and José Pérez-Rigueiro and Christian Riekel and G. Belén Perea and Fernando Agulló-Rueda and Manfred Burghammer and Manuel Elices and Gustavo V. Guinea},
title = {Relationship between microstructure and mechanical properties in spider silk fibers: two regimes in the microstructural changes},
journal = {Soft Matter},
year = {2012},
volume = {8},
number = {22},
pages = {6015--6026},
url = {http://dx.doi.org/10.1039/C2SM25446H},
doi = {10.1039/C2SM25446H}
}
|
| Rosales I, Thions-Renero C, Martinez E, Agulló-Rueda F, Bucio L and Orozco E (2012), "Raman analysis of an impacted α-GeO_2--H_2O mixture", High Pressure Res.. Vol. 32(3), pp. 396-404. |
| Abstract: Through a Raman analysis, we detected polymorphism at high pressure on mixtures of α-GeO_2 microcrystalline powder and water under impact experiments with a single-stage gas gun. The Raman measurements taken from recovered samples show two vibrational modes associated with water-related species. After the impact, the size of the α-GeO_2 crystallites was approximately 10 times higher showing molten zones and a lot of porous faces. Raman examination showed some unknown peaks possibly associated with other GeO_2 polymorphs detected by X-ray diffraction experiments and perhaps stabilized in the porous of the α-GeO_2 crystallites. |
BibTeX:
@article{Rosales2012HPR,
author = {Rosales, Ivonne and Thions-Renero, Claude and Martinez, Erendira and Agulló-Rueda, Fernando and Bucio, Lauro and Orozco, Eligio},
title = {Raman analysis of an impacted α-GeO_2--H_2O mixture},
journal = {High Pressure Res.},
year = {2012},
volume = {32},
number = {3},
pages = {396--404},
url = {http://dx.doi.org/10.1080/08957959.2012.710233},
doi = {10.1080/08957959.2012.710233}
}
|
| Sáenz de Viteri V, Barandika MG, Ruiz de Gopegui U, Bayón R, Zubizarreta C, Fernández X, Igartua A and Agulló-Rueda F (2012), "Characterization of Ti-C-N coatings deposited on Ti6Al4V for biomedical applications", J. Inorg. Biochem.. Vol. 117, pp. 359-366. |
| Abstract: Ti6Al4V alloy is the most commonly employed implant material for orthopedic replacements due to its good mechanical properties close to those of bones, biocompatibility and its good corrosion resistance in biological media. Nevertheless, it does not exhibit good wear resistance, showing friction and wear even with soft tissues. This latter feature can lead to a premature failure of the implant with the subsequent component replacement. Therefore, a system with good tribological resistance is required for several medical applications. One possible alternative to solve tribological problems consists of protecting the alloy surface by means of biocompatible Ti-C-N coatings. In this work, five types of metallic Ti-C-N coatings deposited by physical vapor deposition (PVD) cathodic arc method on Ti6Al4V substrate have been studied. Different deposition conditions have been analyzed, and the superficial properties of films have been characterized. Additionally, tribological response of these films have been determined and compared with the substrate one under fretting conditions in simulated body fluid. The results indicate that Ti-C-N coatings improve the general response of the biomaterial. |
BibTeX:
@article{SaenzDeViteri2012JIBC,
author = {Sáenz de Viteri, V. and Barandika, M. G. and Ruiz de Gopegui, U. and Bayón, R. and Zubizarreta, C. and Fernández, X. and Igartua, A. and Agulló-Rueda, F.},
title = {Characterization of Ti-C-N coatings deposited on Ti6Al4V for biomedical applications},
journal = {J. Inorg. Biochem.},
year = {2012},
volume = {117},
pages = {359--366},
url = {https://doi.org/10.1016/j.jinorgbio.2012.09.012},
doi = {10.1016/j.jinorgbio.2012.09.012}
}
|
| Torres-Costa V, de Melo C, Climent-Font A, Agulló-Rueda F and de Melo O (2012), "Isothermal close space sublimation for II-VI semiconductor filling of porous matrices", Nanoscale Res. Lett.., July, 2012. Vol. 7(1), pp. 409. |
| Abstract: Isothermal close space sublimation, a simple and low cost physical vapor transport technique, was used to infiltrate ZnTe and CdSe semiconductors in porous silicon (PS). The structure of the embedded materials was determined by x-ray diffraction analysis while Rutherford backscattering spectra allowed determining the composition profiles of the samples. In both cases, it was found a constant composition of the II-VI semiconductors throughout the porous layer down to the substrate. The infiltration of the pores is also verified qualitatively by reflectance measurements. Resonance Raman scattering of the ZnTe samples indicates that this semiconductor grows in nanostructured form inside the pores. Results presented in this paper suggest that Isothermal close-space sublimation (ICSS) is a promising technique for the conformal growth of II-VI semiconductor in porous silicon. |
BibTeX:
@article{TorresCosta2012NRL,
author = {Torres-Costa, Vicente and de Melo, Claudia and Climent-Font, Aurelio and Agulló-Rueda, Fernando and de Melo, Osvaldo},
title = {Isothermal close space sublimation for II-VI semiconductor filling of porous matrices},
journal = {Nanoscale Res. Lett.},
year = {2012},
volume = {7},
number = {1},
pages = {409},
url = {https://doi.org/10.1186/1556-276X-7-409},
doi = {10.1186/1556-276X-7-409}
}
|
| Elices M, Guinea G, Plaza G, Karatzas C, Riekel C, Agulló-Rueda F, Daza R and Pérez-Rigueiro J (2011), "Bioinspired fibers follow the track of natural spider silk", Macromolecules. Vol. 44(5), pp. 1166-1176. |
| Abstract: The mechanical behavior and microstructure of bioinspired fibers spun from solutions of recombinant spidroin-like proteins were extensively characterized, and compared with those of natural spider silk fibers. It is confirmed that high performance bioinspired fibers indistinguishable from natural spider silk up to large strains can be produced through genetic engineering and conventional spinning technologies. It is also found that fibers spun from spidroin-like proteins that contain different motifs of sequence exhibit variations in their microstructure in terms of crystallinity and chain alignment, but these differences are not reflected in distinct tensile properties. This similarity in terms of their mechanical behavior indicates that bioinspired fibers are largely independent of their exact sequence of recombinant proteins and, in particular, of their proline content. Finally, it is shown that the largest differences between natural and bioinspired fibers are found at very large deformations, marking the ultimate challenge in the synthesis of silk-like fibers. |
BibTeX:
@article{Elices2011MM,
author = {Elices, Manuel and Guinea, Gustavo and Plaza, Gustavo and Karatzas, Costas and Riekel, Christian and Agulló-Rueda, Fernando and Daza, Rafael and Pérez-Rigueiro, José},
title = {Bioinspired fibers follow the track of natural spider silk},
journal = {Macromolecules},
year = {2011},
volume = {44},
number = {5},
pages = {1166--1176},
url = {http://dx.doi.org/10.1021/ma102291m},
doi = {10.1021/ma102291m}
}
|
| Gabás M, D\iaz-Carrasco P, Agulló-Rueda F, Herrero P, Landa-Cánovas AR and Ramos-Barrado JR (2011), "High quality ZnO and Ga:ZnO thin films grown onto crystalline Si (100) by RF magnetron sputtering", Sol. Energy Mater. Sol. Cells. Vol. 95, pp. 2327-2334. |
| Abstract: Undoped and 2% Ga-doped ZnO films have been deposited by RF magnetron sputtering onto single crystal Si (100) substrates equivalent to the commercial Si solar cells. The same films were also grown on amorphous silica substrates to complete their characterization. The films have been characterized by X-ray diffraction, electrical and optical measurements, X-ray photoelectron spectroscopy, Raman microspectroscopy and scanning and high-resolution transmission electron microscopy. Films present a very good quality crystalline wurtzite structure with the c-axis perpendicular to the substrate, with continuity of the (0002) planes along the whole film, as shown by transmission electron microscopy. The doped sample shows an increase of two orders of magnitude of the electrical conductivity, an optical transmittance bigger than 85% along the visible spectrum, a diminution of the grain size in the direction parallel to the substrate and a lower surface roughness. The Ga-cations act only as substitutional impurities, they are homogeneously distributed in the whole film, maintaining the wurtzite structure and increasing the carrier density. The formation of any spurious phase or segregation of Ga2O3 clusters that can act as carrier traps can be discarded. The characterization results allow us to conclude that the doped film has improved electrical and optical properties with respect to the undoped one. Therefore, the Ga-doped films are very suitable candidates as transparent conducting electrodes for solar cells, displays and other photoelectronic devices. |
BibTeX:
@article{Gabas2011SEMSC,
author = {Gabás, M. and D\iaz-Carrasco, P. and Agulló-Rueda, F. and Herrero, P. and Landa-Cánovas, A. R. and Ramos-Barrado, J. R.},
title = {High quality ZnO and Ga:ZnO thin films grown onto crystalline Si (100) by RF magnetron sputtering},
journal = {Sol. Energy Mater. Sol. Cells},
year = {2011},
volume = {95},
pages = {2327--2334},
url = {http://dx.doi.org/10.1016/j.solmat.2011.04.001},
doi = {10.1016/j.solmat.2011.04.001}
}
|
| Punzón Quijorna E, Torres Costa V, Agulló-Rueda F, Herrero Fernández P, Climent A, Rossi F and Manso Silván M (2011), "TiN_xO_y/TiN dielectric contrasts obtained by ion implantation of O^2+; structural, optical and electrical properties", J. Phys. D: Appl. Phys.. Vol. 44(23), pp. 235501. |
| Abstract: The properties of TiN can be gradually transformed by O_2^+ implantations in the 10--40 keV range and fluences in the 5 × 10^13--5 × 10^16 cm^-2 range. The resulting structure consists of shallow TiN_xO_y(TiNO)/TiN contrasts with increased resistivity on the top layer. In fact, oxygen actively replaces nitrogen in the implanted TiN region as illustrated by Rutherford backscattering spectrometry. N substitutions and vacancies in the lattice induce structural distortions and strain generation as illustrated by x-ray diffraction, high resolution transmission electron microscopy and Raman spectroscopy. The influence of these modifications in the optical and electrical properties was characterized by spectroscopic ellipsometry and four probe resistivity measurements. The proposed process, especially at the lower energy, is liable to help in the creation of electrical/photonic structures based in shallow TiNO/TiN electric/dielectric contrasts. |
BibTeX:
@article{PunzonQuijorna2011JPD,
author = {Punzón Quijorna, E. and Torres Costa, V. and Agulló-Rueda, F. and Herrero Fernández, P. and Climent, A. and Rossi, F. and Manso Silván, M.},
title = {TiN_xO_y/TiN dielectric contrasts obtained by ion implantation of O^2+; structural, optical and electrical properties},
journal = {J. Phys. D: Appl. Phys.},
year = {2011},
volume = {44},
number = {23},
pages = {235501},
url = {http://dx.doi.org/10.1088/0022-3727/44/23/235501},
doi = {10.1088/0022-3727/44/23/235501}
}
|
| Barranco V, Lillo-Rodenas MA, Linares-Solano A, Oya A, Pico F, Ibañez J, Agulló-Rueda F, Amarilla JM and Rojo JM (2010), "Amorphous Carbon Nanofibers and Their Activated Carbon Nanofibers as Supercapacitor Electrodes", J. Phys. Chem. C., June, 2010. Vol. 114(22), pp. 10302-10307. |
| Abstract: Carbon nanofibers (CNFs) show a high electrical conductivity but a reduced specific surface area that limits their use as electrode materials for supercapacitors. In this work, amorphous CNFs, with a relatively high electrical conductivity are easily activated in KOH, using certain KOH/CNF weight ratios. Activation does not produce any important change in the shape, surface roughness, diameter, graphene sheet size, and electrical conductivity of starting nanofibers. However, activation leads to new micropores and larger surface areas as well as a higher content of basic oxygen groups. They clearly enhanced the specific capacitance, attaining values higher than those reported for other activated CNFs. In this study, the effects of micropore size and oxygen content on the specific capacitance are discussed for three electrolytes: H_2SO_4, KOH, and (CH_3CH_2)_4NBF_4. Moreover, a good cycle life is found for the most activated CNFs. |
BibTeX:
@article{Barranco2010JPCC,
author = {V. Barranco and M. A. Lillo-Rodenas and A. Linares-Solano and A. Oya and F. Pico and J. Ibañez and F. Agulló-Rueda and J. M. Amarilla and J. M. Rojo},
title = {Amorphous Carbon Nanofibers and Their Activated Carbon Nanofibers as Supercapacitor Electrodes},
journal = {J. Phys. Chem. C},
year = {2010},
volume = {114},
number = {22},
pages = {10302--10307},
url = {http://dx.doi.org/10.1021/jp1021278},
doi = {10.1021/jp1021278}
}
|
| Buijnsters JG, Camero M, Vázquez L, Agulló-Rueda F, Gago R, Jiménez I, Gómez-Aleixandre C and Albella JM (2010), "Tribological study of hydrogenated amorphous carbon films with tailored microstructure and composition produced by bias-enhanced plasma chemical vapour deposition", Diamond Relat. Mater.. Vol. 19(7-9), pp. 1093-1102. |
| Abstract: We investigated the mechanical and tribological properties of hydrogenated amorphous carbon (a-C:H) films on silicon substrates by nanoindentation, ball-on-disc tribotesting and scratch testing. The a-C:H films were deposited from an argon/methane gas mixture by bias-enhanced electron cyclotron resonance chemical vapour deposition (ECR-CVD). We found that substrate biasing directly influences the hardness, friction and wear resistance of the a-C:H films. An abrupt change in these properties is observed at a substrate bias of about -100 V, which is attributed to the bias-controlled transition from polymer- to fullerenelike carbon coatings. Friction coefficients in the range of 0.28--0.39 and wear rates of about 7 × 10^-5 mm^3/Nm are derived for the polymeric films when tested against WC-Co balls at atmospheric test conditions. On the other hand, the fullerenelike hydrogenated carbon films produced at ion energies > 100 eV display a nanohardness of about 17 GPa, a strong reduction in the friction coefficient (≈ 0.10) and a severe increase in the wear resistance (≈ 1 × 10^-7 mm^3/Nm). For these films, relative humidity has a detrimental effect on friction but no correlation with the wear rate was found. |
BibTeX:
@article{Buijnsters2010DRM,
author = {J. G. Buijnsters and M. Camero and L. Vázquez and F. Agulló-Rueda and R. Gago and I. Jiménez and C. Gómez-Aleixandre and J. M. Albella},
title = {Tribological study of hydrogenated amorphous carbon films with tailored microstructure and composition produced by bias-enhanced plasma chemical vapour deposition},
journal = {Diamond Relat. Mater.},
year = {2010},
volume = {19},
number = {7--9},
pages = {1093--1102},
url = {http://dx.doi.org/10.1016/j.diamond.2010.03.017},
doi = {10.1016/j.diamond.2010.03.017}
}
|
| Buijnsters JG, Gago R, Jiménez I, Camero M, Agulló-Rueda F and Gómez-Aleixandre C (2009), "Hydrogen quantification in hydrogenated amorphous carbon films by infrared, Raman and x-ray absorption near edge spectroscopies", J. Appl. Phys.. Vol. 105(9), pp. 093510. |
| Abstract: In this study, we have employed infrared (IR) absorption spectroscopy, visible Raman spectroscopy, and x-ray absorption near edge structure (XANES) to quantify the hydrogen (H) content in hydrogenated amorphous carbon (a-C:H) films. a-C:H films with a hydrogen content varying from 29 to 47 at. % have been synthesized by electron cyclotron resonance chemical vapor deposition at low substrate temperatures (<120^circ°C) applying a wide range of bias voltage, V_b, (-300 V < V_b < +100 V). With the application of high negative V_b, the a-C:H films undergo a dehydrogenation process accompanied by a sharp structural modification from polymer- to fullerenelike films. The trend in the H content derived from elastic recoil detection analysis (ERDA) is quantitatively reproduced from the intensity of the C--H bands and states in the IR and XANES spectra, respectively, as well as from the photoluminescence (PL) background drop in the Raman spectra. Using the H contents obtained by ERDA as reference data, semiquantitative expressions are inferred for the amount of bonded hydrogen as a function of the experimental spectroscopic parameters, i.e., the integrated area of the IR C--H stretching band at about 2900 cm^-1, the PL background in visible Raman spectra, and the XANES intensity of the -CH peak. |
BibTeX:
@article{Buijnsters2009HYD,
author = {J. G. Buijnsters and R. Gago and I. Jiménez and M. Camero and F. Agulló-Rueda and C. Gómez-Aleixandre},
title = {Hydrogen quantification in hydrogenated amorphous carbon films by infrared, Raman and x-ray absorption near edge spectroscopies},
journal = {J. Appl. Phys.},
year = {2009},
volume = {105},
number = {9},
pages = {093510},
url = {http://dx.doi.org/10.1063/1.3103326},
doi = {10.1063/1.3103326}
}
|
| Plaza G, Corsini P, Marsano E, Pérez-Rigueiro J, Biancotto L, Elices M, Riekel C, Agulló-Rueda F, Gallardo E, Calleja JM and Guinea G (2009), "Old silks endowed with new properties", Macromolecules. Vol. 42(22), pp. 8977-8982. |
| Abstract: High-performance regenerated silkworm Bombyx mori silk fibers with new properties that mimic those of spider silk can be produced through a wet spinning process modified with an immersion postspinning drawing (IPSD) step. IPSD fibers show the ability to recover from irreversible deformation, and their tensile behavior can be tailored repeatedly, features solely exhibited until now by natural spider silk. It is further shown that the new properties emerge from a microstructure that is closer to that of spider than to natural silkworm silk. This work demonstrates that processing plays a role at least comparable to that of the amino acid sequence in the final properties of the material. The spinning process does not only modify the mechanical parameters of the fiber but also can even prompt the emergence of new properties, opening a wide range of new applications for regenerated silk fibers. It also represents a significant change of the paradigm in the field of biomimetics, given that it relaxes the condition of copying the natural protein sequences as close as possible to recover the outstanding properties of the natural materials. |
BibTeX:
@article{Plaza2009MM,
author = {Plaza, Gustavo and Corsini, Paola and Marsano, Enrico and Pérez-Rigueiro, José and Biancotto, Lautaro and Elices, Manuel and Riekel, Christian and Agulló-Rueda, Fernando and Gallardo, Eva and Calleja, José Manuel and Guinea, Gustavo},
title = {Old silks endowed with new properties},
journal = {Macromolecules},
year = {2009},
volume = {42},
number = {22},
pages = {8977--8982},
url = {http://dx.doi.org/10.1021/ma9017235},
doi = {10.1021/ma9017235}
}
|
| Rivera A, Olivares J, Garc\ia G, Cabrera JM, Agulló-Rueda F and Agulló-López F (2009), "Giant enhancement of material damage associated to electronic excitation during ion irradiation: The case of LiNbO_3", Phys. Status Solidi A. Vol. 206(6), pp. 1109-1116. |
BibTeX:
@article{Rivera2009,
author = {A. Rivera and J. Olivares and G. Garc\ia and J. M. Cabrera and F. Agulló-Rueda and F. Agulló-López},
title = {Giant enhancement of material damage associated to electronic excitation during ion irradiation: The case of LiNbO_3},
journal = {Phys. Status Solidi A},
year = {2009},
volume = {206},
number = {6},
pages = {1109--1116},
url = {http://dx.doi.org/10.1002/pssa.200824409},
doi = {10.1002/pssa.200824409}
}
|
| Agulló-Rueda F (2008), "Espectroscop\ia Raman", In La ciencia y el arte: Ciencias experimentales y conservación del Patrimonio Histórico. Madrid , pp. 117-125. Subdirección General del Instituto del Patrimonio Histórico Español. |
BibTeX:
@incollection{AgulloRueda08IPH,
author = {Agulló-Rueda, Fernando},
editor = {Prous, Socorro and Egido, Marián del and Calderón, Tomás},
title = {Espectroscop\ia Raman},
booktitle = {La ciencia y el arte: Ciencias experimentales y conservación del Patrimonio Histórico},
publisher = {Subdirección General del Instituto del Patrimonio Histórico Español},
year = {2008},
pages = {117--125},
url = {https://dialnet.unirioja.es/servlet/articulo?codigo=2671990}
}
|
| Lazić S, Gallardo E, Calleja JM, Agulló-Rueda F, Grandal J, Sánchez-Garcia MA and Calleja E (2008), "Raman scattering by longitudinal optical phonons in InN nanocolumns grown on Si(111) and Si(001) substrates", Physica E. Vol. 40(6), pp. 2087-2090. |
| Abstract: Raman measurements in high-quality InN nanocolumns and thin films grown on both Si(1 1 1) and Si(1 0 0) substrates display a low-energy coupled LO phonon–plasmon mode together with uncoupled longitudinal optical (LO) phonons. The coupled mode is attributed to the spontaneous accumulation of electrons on the lateral surfaces of the nanocolumns, while the uncoupled ones originates from the inner part of the nanocolumns. The LO mode in the columnar samples appears close to the E_1(LO) frequency. This indicates that most of the incident light is entering through the lateral surfaces of the nanocolumns, resulting in pure longitudinal-optical mode with quasi-E_1 symmetry. For increasing growth temperature, the electron density decreases as the growth rate increases. The present results indicate that electron accumulation layers do not only form on polar surfaces of InN, but also occur on non-polar ones. According to recent calculations, we attribute the electron surface accumulation to the temperature dependent In-rich surface reconstruction on the nanocolumns sidewalls. |
BibTeX:
@article{Lazic08PhE,
author = {S. Lazić and E. Gallardo and J. M. Calleja and F. Agulló-Rueda and J. Grandal and M. A. Sánchez-Garcia and E. Calleja},
title = {Raman scattering by longitudinal optical phonons in InN nanocolumns grown on Si(111) and Si(001) substrates},
journal = {Physica E},
year = {2008},
volume = {40},
number = {6},
pages = {2087--2090},
note = {http://www.ep2ds-mss.infm.it/ 13th International Conference on Modulated Semiconductor Structures, Genova, Italy, 15--20 July 2007.},
url = {http://dx.doi.org/10.1016/j.physe.2007.09.118},
doi = {10.1016/j.physe.2007.09.118}
}
|
| Lazić S, Gallardo E, Calleja JM, Agulló-Rueda F, Grandal J, Sánchez-Garc\ia MA and Calleja E (2008), "Raman scattering by coupled plasmon-LO phonons in InN nanocolumns", Phys. Status Solidi C. Vol. 5(6), pp. 1562-1564. |
| Abstract: Raman measurements on high quality, relaxed InN nanocolumns grown on Si(001) and Si(111) substrates by plasma-assisted molecular beam epitaxy are reported. A coupled LO phonon-plasmon mode around 430 cm^-1, together with the uncoupled LO phonon appears in the nanocolumnar samples. The coupled mode is attributed to spontaneous accumulation of electrons at the lateral surfaces of the nanocolumns, while the uncoupled phonon originates from their inner part. Infrared reflectance measurements confirm the presence of electrons in the nanocolumns. The electron density in the accumulation layer depends on the growth temperature and is sensitive to exposure of HCl. Our results indicate that accumulation of intrinsic electrons occurs not only at the polar surfaces of InN layers, but also on non-polar lateral surfaces of InN nanocolumns. Its origin is attributed to an In-rich surface reconstruction of the nanocolumns sidewalls. |
BibTeX:
@article{Lazic2008PSSC,
author = {S. Lazić and E. Gallardo and J. M. Calleja and F. Agulló-Rueda and J. Grandal and M. A. Sánchez-Garc\ia and E. Calleja},
title = {Raman scattering by coupled plasmon-LO phonons in InN nanocolumns},
journal = {Phys. Status Solidi C},
year = {2008},
volume = {5},
number = {6},
pages = {1562--1564},
url = {http://dx.doi.org/10.1002/pssc.200778488},
doi = {10.1002/pssc.200778488}
}
|
| Perales F, Agulló-Rueda F, Lamela J and de las Heras C (2008), "Optical and structural properties of Sb_2S_3/MgF_2 multilayers for laser applications", J. Phys. D.: Appl. Phys.. Vol. 41(4), pp. 045403. |
| Abstract: Multilayers of MgF_2 and Sb_2S_3 have been obtained by physical vapour deposition on glass substrates. Changes in the optical and structural properties have been studied as a function of annealing temperature and the number of layers. A drastic variation in optical transmission, microstrain and grain size is observed at a temperature near 225^circC. A comparison of the material properties of multilayers and a monolayer is carried out. |
BibTeX:
@article{Perales08JPD,
author = {F. Perales and F. Agulló-Rueda and J. Lamela and C. de las Heras},
title = {Optical and structural properties of Sb_2S_3/MgF_2 multilayers for laser applications},
journal = {J. Phys. D.: Appl. Phys.},
year = {2008},
volume = {41},
number = {4},
pages = {045403},
url = {http://dx.doi.org/10.1088/0022-3727/41/4/045403},
doi = {10.1088/0022-3727/41/4/045403}
}
|
| Ballesteros B, de la Torre G, Ehli C, Aminur Rahman GM, Agulló-Rueda F, Guldi DM and Torres T (2007), "Single-wall carbon nanotubes bearing covalently linked phthalocyanines - Photoinduced electron transfer", J. Am. Chem. Soc.. Vol. 129(16), pp. 5061-5068. |
| Abstract: HiPco single-walled carbon nanotubes (SWNTs) have been sidewall-functionalized with phthalocyanine addends following two different approaches: a straightforward Prato reaction with N-octylglycine and a formyl-containing phthalocyanine, and a stepwise approach that involves a former Prato cycloaddition to the double bonds of SWNTs using p-formyl benzoic acid followed by esterification of the derivatized nanotubes with an appropriate phthalocyanine molecule. The two materials obtained by these routes comprise different carbon/Pc-addenda ratios, as evidenced by Raman, TGA, and photophysical studies. The occurrence of electron transfer from photoexcited phthalocyanines to the nanotube framework in these ZnPc-SWNT ensembles is observed in transient absorption experiments, which confirm the absorption of the one-electron oxidized ZnPc cation and the concomitant bleaching of the van Hove singularities typical from SWNTs. Charge-separation (i.e., 2.0 × 10^10 s^-1) and charge-recombination (i.e., 1.5 × 10^6 s^-1) dynamics reveal a notable stabilization of the radical ion pair product in dimethylformamide. |
BibTeX:
@article{Ballesteros07,
author = {Ballesteros, Beatriz and de la Torre, Gema and Ehli, Christian and Aminur Rahman, G. M. and Agulló-Rueda, F. and Guldi, Dirk M. and Torres, Tomás},
title = {Single-wall carbon nanotubes bearing covalently linked phthalocyanines - Photoinduced electron transfer},
journal = {J. Am. Chem. Soc.},
year = {2007},
volume = {129},
number = {16},
pages = {5061--5068},
url = {http://dx.doi.org/10.1021/ja068240n},
doi = {10.1021/ja068240n}
}
|
| Buijnsters JG, Camero M, Vázquez L, Agulló-Rueda F, Gómez-Aleixandre C and Albella JM (2007), "DC substrate bias effects on the physical properties of hydrogenated amorphous carbon films grown by plasma-assisted chemical vapour deposition", Vacuum., In Proceedings of the selected presentations from Sixth Iberian Vacuum Meeting and Fourth European Topical Conference on Hard Coatings, 26--28 June 2006. Salamanca, Spain. Diamond and Other New Carbon Materials IV. Vol. 81(11-12), pp. 1412-1415. |
| Abstract: In the present work, a-C:H films have been grown from argon/methane gas mixtures by Electron Cyclotron Resonance Chemical Vapour Deposition (ECRCVD). The effect of the application of a dc bias voltage to the silicon substrate material on the structural, morphological and mechanical properties of the films has been explored by multiple analysis techniques such as IR and micro-Raman spectroscopy, AFM, nano-indentation and pin-ondisk wear testing. In general, within the range of -300 V to +100 V applied substrate bias we have observed a strong correlation between all measured properties of the grown a-C:H films and the ion energy. Though it is known that the ion energy is one of the crucial parameters in plasma grown films, this work clearly shows that the properties of the a-C:H layers can differ greatly and indicates a threshold energy for the production of hard, low-friction coatings in the order of 80--90 eV. Moreover, this threshold energy is also combined with a sharp transition from rough, cauliflower-like film surfaces towards ultrasmooth, featureless topographies. This correlation suggests that at energies higher than 80 eV the ion bombardment affects simultaneously the surface morphology and the internal bonding structure. |
BibTeX:
@article{Buijnsters07,
author = {Buijnsters, J. G. and Camero, M. and Vázquez, L. and Agulló-Rueda, F. and Gómez-Aleixandre, C. and Albella, J. M.},
editor = {de Segovia, J. L.},
title = {DC substrate bias effects on the physical properties of hydrogenated amorphous carbon films grown by plasma-assisted chemical vapour deposition},
booktitle = {Proceedings of the selected presentations from Sixth Iberian Vacuum Meeting and Fourth European Topical Conference on Hard Coatings, 26--28 June 2006. Salamanca, Spain. Diamond and Other New Carbon Materials IV},
journal = {Vacuum},
year = {2007},
volume = {81},
number = {11--12},
pages = {1412--1415},
url = {http://dx.doi.org/10.1016/j.vacuum.2007.04.021},
doi = {10.1016/j.vacuum.2007.04.021}
}
|
| Calleja JM, Lazić S, Sanchez-Páramo J, Agulló-Rueda F, Cerutti L, Ristić J, Fernández-Garrido S, Sánchez-Garcia MA, Grandal J, Calleja E, Trampert A and Jahn U (2007), "Inelastic light scattering spectroscopy of semiconductor nitride nanocolumns", Phys. Status Solidi B. Vol. 244(8), pp. 2838-2846. |
| Abstract: A review of inelastic light scattering measurements on group III‐nitride nanocolumns grown by molecular beam epitaxy is presented. The nanocolumns are hexagonal, high quality single crystals with diameters in the range of 20 to 100 nm, with no traces of extended defects. GaN nanocolumns grown on bare Si substrates with both (111) and (100) orientation display narrow phonon peaks, indicating the absence of strain inhomogeneities. This opens the possibility of efficient integration of the nanocolumns as optoelectronic devices with the complementary metal oxide semiconductor technology. Measurements of the E_2 phonon frequency on AlGaN nanocolumns indicate a linear dependence of the Al concentration on the Al relative flux, up to 60%. The E_2 peak width increases with Al content due to phonon damping by alloy scattering. Inelastic light scattering measurements in InN nanocolumns display a coupled LO phonon‐plasmon mode together with uncoupled phonons. The coupled mode is not observed in a reference compact sample. The origin of the coupled mode is attributed to spontaneous accumulation of electrons at the lateral surfaces of the nanocolumns. The presence of free electrons in the nanocolumns is confirmed by infrared reflectance measurements. |
BibTeX:
@article{Calleja07pss,
author = {J. M. Calleja and S. Lazić and J. Sanchez-Páramo and F. Agulló-Rueda and L. Cerutti and J. Ristić and S. Fernández-Garrido and M. A. Sánchez-Garcia and J. Grandal and E. Calleja and A. Trampert and U. Jahn},
title = {Inelastic light scattering spectroscopy of semiconductor nitride nanocolumns},
journal = {Phys. Status Solidi B},
year = {2007},
volume = {244},
number = {8},
pages = {2838--2846},
url = {http://dx.doi.org/10.1002/pssb.200675610},
doi = {10.1002/pssb.200675610}
}
|
| Katcho N, Urones-Garrote E, Ávila-Brande D, Gómez-Herrero A, Svensson G, Csillag S, Lomba E, Agulló-Rueda F, Landa-Cánovas AR and Otero-D\iaz LC (2007), "Carbon hollow nanospheres from chlorination of ferrocene", Chem. Mater.. Vol. 19(9), pp. 2304-2309. |
| Abstract: The chlorination of ferrocene at 900^circC yields very interesting carbon hollow nanospheres (CHNSs) with diameters of aapprox 50--150 nm and ≈ 12--25 nm thick walls. X-ray energy-dispersive spectroscopy shows no traces of chlorine or iron and the / ratio of the carbon bonding was quantified by electron energy-loss spectroscopy with 80% sp^2 (100% sp^2 for pure graphite). Energy-filtered transmission electron microscopy has been used to establish the hollow nature of the CHNSs by thickness mapping. Electron energy loss spectroscopy, high-resolution TEM, and Raman microspectroscopy techniques have stated that the CHNS carbon walls are composed of disordered and independent curved graphene nanoflakes ≈ 3--4 nm long that tend to graphitize with longer reaction times. |
BibTeX:
@article{Katcho07,
author = {N. Katcho and E. Urones-Garrote and D. Ávila-Brande and A. Gómez-Herrero and G. Svensson and S. Csillag and E. Lomba and F. Agulló-Rueda and A. R. Landa-Cánovas and L. C. Otero-D\iaz},
title = {Carbon hollow nanospheres from chlorination of ferrocene},
journal = {Chem. Mater.},
year = {2007},
volume = {19},
number = {9},
pages = {2304--2309},
url = {http://dx.doi.org/10.1021/cm062997w},
doi = {10.1021/cm062997w}
}
|
| Lazić S, Gallardo E, Calleja JM, Agulló-Rueda F, Grandal J, Sánchez-Garcia MA, Calleja E, Luna E and Trampert A (2007), "Phonon-plasmon coupling in electron surface accumulation layers in InN nanocolumns", Phys. Rev. B. Vol. 76(20), pp. 205319. APS. |
| Abstract: Raman measurements in high quality InN nanocolumns display a coupled LO phonon-plasmon mode together with uncoupled phonons. The coupled mode is attributed to the spontaneous accumulation of electrons on the lateral surfaces of the nanocolumns. For increasing growth temperature, the electron density decreases as the growth rate increases. The present results indicate that electron accumulation layers do not only form on polar surfaces of InN but also occur on nonpolar ones. According to recent calculations, we attribute the electron surface accumulation to the temperature dependent In-rich surface reconstruction on the nanocolumn sidewalls. |
BibTeX:
@article{Lazic07PRB,
author = {S. Lazić and E. Gallardo and J. M. Calleja and F. Agulló-Rueda and J. Grandal and M. A. Sánchez-Garcia and E. Calleja and E. Luna and A. Trampert},
title = {Phonon-plasmon coupling in electron surface accumulation layers in InN nanocolumns},
journal = {Phys. Rev. B},
publisher = {APS},
year = {2007},
volume = {76},
number = {20},
pages = {205319},
url = {http://dx.doi.org/10.1103/PhysRevB.76.205319},
doi = {10.1103/PhysRevB.76.205319}
}
|
| Manso-Silván M, Navas C, Arroyo-Hernández M, López-Elvira E, Gago R, Vázquez L, Agulló-Rueda F, Climent A, Mart\inez-Duart JM and Garc\ia-Ruiz P (2007), "Hybrid titania/aminosilane coatings as platforms for the evaluation of Human Mesenchymal Stem Cells", J. Biomed. Mater. Res. B. Vol. 83B(1), pp. 232-239. |
| Abstract: The properties of hybrid aminopropyltriethoxysilane-tetraisopropylorthotitanate (APTS-TIPT) platforms prepared by a sol-gel route have been explored, and their biocompatibility was assayed after culture of human mesenchymal stem cells (hMSCs). The organic content of this material was observed to be preferably surface-oriented as indicated by microanalytical techniques. Furthermore, the surface showed characteristic amino-silane bands when explored by Raman spectroscopy as well as indications of silane and titanate condensation. Surface activity of the amino groups was probed by ultraviolet-visible spectroscopy imine derivatization and chemical force spectroscopy, showing a pH-dependent surface charge-induced potential. hMSCs cultured onto these surfaces showed relevant differences with respect to their behavior on gelatin-coated glass plates. Even if with a lower proliferative rate than controls, the cells develop long cytosolic prolongations in osteogenic differentiation medium, thus, supporting the idea of an APTS-TIPT stimulated process. |
BibTeX:
@article{Manso-Silvan07,
author = {M. Manso-Silván and C. Navas and M. Arroyo-Hernández and E. López-Elvira and R. Gago and L. Vázquez and F. Agulló-Rueda and A. Climent and J. M. Mart\inez-Duart and P. Garc\ia-Ruiz},
title = {Hybrid titania/aminosilane coatings as platforms for the evaluation of Human Mesenchymal Stem Cells},
journal = {J. Biomed. Mater. Res. B},
year = {2007},
volume = {83B},
number = {1},
pages = {232--239},
url = {http://dx.doi.org/10.1002/jbm.b.30788},
doi = {10.1002/jbm.b.30788}
}
|
| Mart\inez-Duart JM, Mart\in-Palma RJ and Agulló-Rueda F (2007), "Nanotechnologii dlya micro- i optoelectroniki" Moscow, Russia Technosphera. |
BibTeX:
@book{Martinez-Duart2007R,
author = {Mart\inez-Duart, José Manuel and Mart\in-Palma, Raul José and Agulló-Rueda, Fernando},
title = {Nanotechnologii dlya micro- i optoelectroniki},
publisher = {Technosphera},
year = {2007},
url = {http://www.technosphera.ru/lib/book/75}
}
|
| Olivares J, Garc\ia-Navarro A, Garc\ia G, Agulló-López F, Agulló-Rueda F, Garc\ia-Cabañes A and Carrascosa M (2007), "Buried amorphous layers by electronic excitation in ion-beam irradiated lithium niobate: structure and kinetics", J. Appl. Phys.. Vol. 101(3), pp. 033512. |
| Abstract: The formation of buried heavily damaged and amorphous layers by a variety of swift-ion irradiations (F at 22MeV, O at 20MeV, and Mg at 28MeV) on congruent LiNbO_3 has been investigated. These irradiations assure that the electronic stopping power Se(z) is dominant over the nuclear stopping S_n(z) and reaches a maximum value inside the crystal. The structural profile of the irradiated layers has been characterized in detail by a variety of spectroscopic techniques including dark-mode propagation, micro-Raman scattering, second-harmonic generation, and Rutherford backscattering spectroscopy∕channeling. The growth of the damage on increasing irradiation fluence presents two differentiated stages with an abrupt structural transition between them. The heavily damaged layer reached as a final stage is optically isotropic (refractive index n = 2.10, independent of bombarding ion) and has an amorphous structure. Moreover, it has sharp profiles and its thickness progressively increases with irradiation fluence. The dynamics under irradiation of the amorphous-crystalline boundaries has been associated with a reduction of the effective amorphization threshold due to the defects created by prior irradiation (cumulative damage). The kinetics of the two boundaries of the buried layer is quite different, suggesting that other mechanisms aside from the electronic stopping power should play a role on ion-beam damage. |
BibTeX:
@article{Olivares07,
author = {Olivares, J. and Garc\ia-Navarro, A. and Garc\ia, G. and Agulló-López, F. and Agulló-Rueda, F. and Garc\ia-Cabañes, A. and Carrascosa, M.},
title = {Buried amorphous layers by electronic excitation in ion-beam irradiated lithium niobate: structure and kinetics},
journal = {J. Appl. Phys.},
year = {2007},
volume = {101},
number = {3},
pages = {033512},
url = {http://dx.doi.org/10.1063/1.2434801},
doi = {10.1063/1.2434801}
}
|
| Perales F, Lifante G, Agulló-Rueda F and de las Heras C (2007), "Optical and structural properties in the amorphous to polycrystalline transition in Sb_2S_3 thin films", J. Phys. D: Appl. Phys.. Vol. 40(8), pp. 2440-2444. |
| Abstract: Sb_2S_3 thin films have been obtained by physical vapour deposition on LiNbO_3 and glass substrates. Films with amorphous structure originally became polycrystalline by annealing in a sulfur atmosphere. Changes in optical and structural properties have been studied as a function of annealing temperature. A drastic variation in optical transmission, energy gaps, refractive index, crystallite size, etc is observed at a temperature near 200^circC. |
BibTeX:
@article{Perales07JPD,
author = {F. Perales and G. Lifante and F. Agulló-Rueda and C. de las Heras},
title = {Optical and structural properties in the amorphous to polycrystalline transition in Sb_2S_3 thin films},
journal = {J. Phys. D: Appl. Phys.},
year = {2007},
volume = {40},
number = {8},
pages = {2440--2444},
url = {http://dx.doi.org/10.1088/0022-3727/40/8/005},
doi = {10.1088/0022-3727/40/8/005}
}
|
| Ródenas A, Jaque D, Molpeceres C, Lauzurica S, Ocaña JL, Torchia GA and Agulló-Rueda F (2007), "Ultraviolet nanosecond laser-assisted micro-modifications in Lithium Niobate monitored by Nd^3+ luminescence", Appl. Phys. A. Vol. 87(1), pp. 87-90. |
| Abstract: This work reports on the microstructural modifications produced by nanosecond ultraviolet ablation in neodymium doped lithium niobate crystals. The neodymium ions have been used as optical probes to determine the extension and nature of the modified bulk material. From micro-luminescence experiments we have been able to determine the spatial distribution of the UV ablation induced material densification, local disorder and defect creation. Results have been compared to those previously obtained from femtosecond irradiated lithium niobate crystals. |
BibTeX:
@article{Rodenas07uv,
author = {Ródenas, A. and Jaque, D. and Molpeceres, C. and Lauzurica, S. and Ocaña, J. L. and Torchia, G. A. and Agulló-Rueda, F.},
title = {Ultraviolet nanosecond laser-assisted micro-modifications in Lithium Niobate monitored by Nd^3+ luminescence},
journal = {Appl. Phys. A},
year = {2007},
volume = {87},
number = {1},
pages = {87--90},
url = {http://dx.doi.org/10.1007/s00339-006-3853-0},
doi = {10.1007/s00339-006-3853-0}
}
|
| Agulló-Rueda F and Agulló-López F (2006), "Fotónica y nanotecnolog\ia", Revista Española de F\isica., January--March, 2006. Vol. 20(1), pp. 12-19. |
| Abstract: In this paper we deal with the intimate connection between photonics and nanotechnology. We will briefly review the optical methods to observe and manipulate nanometric particles and describe how one can modify the photonic response of materials by playing with their nanostructure. |
BibTeX:
@article{Agullo-Rueda06,
author = {F. Agulló-Rueda and F. Agulló-López},
title = {Fotónica y nanotecnolog\ia},
journal = {Revista Española de F\isica},
year = {2006},
volume = {20},
number = {1},
pages = {12--19},
url = {http://revistadefisica.es/index.php/ref/article/view/1670}
}
|
| Buijnsters JG, Camero M, Vázquez L, Agulló-Rueda F, Gómez-Aleixandre C and Albella JM (2006), "Effect of Bias Voltage on the Physical Properties of Hydrogenated Amorphous Carbon Films Grown by Electron Cyclotron Resonance Chemical Vapour Deposition", Adv. Sci. Tecnhnol.., In Diamond and Other New Carbon Materials IV. Vol. 48, pp. 17-23. |
| Abstract: In the present work, a-C:H films have been grown from argon/methane gas mixtures by Electron Cyclotron Resonance Chemical Vapour Deposition (ECRCVD). The effect of the application of a dc bias voltage to the silicon substrate material on the structural, morphological and mechanical properties of the films has been explored by multiple analysis techniques such as IR and micro-Raman spectroscopy, AFM, nano-indentation and pin-ondisk wear testing. In general, within the range of -300 V to +100 V applied substrate bias we have observed a strong correlation between all measured properties of the grown a-C:H films and the ion energy. Though it is known that the ion energy is one of the crucial parameters in plasma grown films, this work clearly shows that the properties of the a-C:H layers can differ greatly and indicates a threshold energy for the production of hard, low-friction coatings in the order of 80--90 eV. Moreover, this threshold energy is also combined with a sharp transition from rough, cauliflower-like film surfaces towards ultrasmooth, featureless topographies. This correlation suggests that at energies higher than 80 eV the ion bombardment affects simultaneously the surface morphology and the internal bonding structure. |
BibTeX:
@article{Buijnsters06,
author = {Buijnsters, J. G. and Camero, M. and Vázquez, L. and Agulló-Rueda, F. and Gómez-Aleixandre, C. and Albella, J. M.},
title = {Effect of Bias Voltage on the Physical Properties of Hydrogenated Amorphous Carbon Films Grown by Electron Cyclotron Resonance Chemical Vapour Deposition},
booktitle = {Diamond and Other New Carbon Materials IV},
journal = {Adv. Sci. Tecnhnol.},
year = {2006},
volume = {48},
pages = {17--23},
url = {https://doi.org/10.4028/www.scientific.net/AST.48.17},
doi = {10.4028/www.scientific.net/AST.48.17}
}
|
| Garc\ia G, Olivares J, Agulló-López F, Garc\ia-Navarro A, Agulló-Rueda F, Garc\ia-Cabañes A and Carrascosa M (2006), "Effect of local rotations on the optical response of LiNbO_3: application to ion-beam damage", Europhys. Lett.. Vol. 76(6), pp. 1123-1129. |
| Abstract: The effect of local rigid rotations of the LiNbO_3 structure on the optical response has been theoretically explored and compared to experimental data obtained after irradiation with F (20--22 MeV), O (20 MeV) and Mg (39 MeV) ions. The calculations account for the main trends of the ordinary and extraordinary refractive indices measured after the initial stage of irradiation, namely, decrease in birrefringence and approximate invariance of the average refractive index. Moreover, experimental data are quantitatively consistent with a distribution function exp [-0] for the rotation angle with respect to the trigonal (Z-axis) and isotropic azimuthal angle φ. The corresponding 0 angle is in the range 4.6--7.0^circ depending on ion and energy (stopping power). The model also predicts a significant reduction in second-harmonic generation (SHG) yield with fluence, comparable although somewhat lower than found by experiment. |
BibTeX:
@article{Garcia06,
author = {G. Garc\ia and J. Olivares and F. Agulló-López and A. Garc\ia-Navarro and F. Agulló-Rueda and A. Garc\ia-Cabañes and M. Carrascosa},
title = {Effect of local rotations on the optical response of LiNbO_3: application to ion-beam damage},
journal = {Europhys. Lett.},
year = {2006},
volume = {76},
number = {6},
pages = {1123--1129},
url = {http://dx.doi.org/10.1209/epl/i2006-10375-2},
doi = {10.1209/epl/i2006-10375-2}
}
|
| Mart\inez-Duart JM, Mart\in-Palma RJ and Agulló-Rueda F (2006), "Nanotechnology for Microelectronics and Optoelectronics" Elsevier. |
| Abstract: When solids are reduced to the nanometer scale, they exibit new and exciting behaviours which constitute the basis for a new generation of electronic devices. Nanotechnology for Microelectronics and Optoelectronics outlines in detail the fundamental solid-state physics concepts that explain the new properties of matter caused by this reduction of solids to the nanometer scale. Applications of these electronic properties is also explored, helping students and researchers to appreciate the current status and future potential of nanotechnology as applied to the electronics industry. |
BibTeX:
@book{Martinez-Duart06,
author = {Mart\inez-Duart, José Manuel and Mart\in-Palma, Raul José and Agulló-Rueda, Fernando},
title = {Nanotechnology for Microelectronics and Optoelectronics},
publisher = {Elsevier},
year = {2006},
url = {https://doi.org/10.1016/B978-0-08-044553-3.X5000-0},
doi = {10.1016/B978-0-08-044553-3.X5000-0}
}
|
| Merchant CA, Aitchison JS, Garcia-Blanco S, Hnatovsky C, Taylor RS, Agulló-Rueda F, Kellock AJ and Baglin JEE (2006), "Direct Observation of Waveguide Formation in KGd(WO_4)_2 by Low Dose H^+ Ion Implantation", Appl. Phys. Lett.. Vol. 89(11), pp. 111116. |
| Abstract: In this letter, a direct measurement of a refractive index change in potassium gadolinium tungstate KGW created by a low-dose ion implantation of 1 MeV hydrogen ions is reported. The characterization was performed using both microreflectivity and Raman spectroscopy measurements. The microreflectivity results show both negative and positive changes in refractive index in the damage region when measuring refractive index along different polarization axes. Micro-Raman spectroscopy analysis shows preservation of the Raman characteristics of KGW in the nondamaged crystal regions. These results show that ion implantation in KGW has a great potential for fabricating waveguide structures in Raman-based photonic devices. |
BibTeX:
@article{Merchant06,
author = {C. A. Merchant and J. S. Aitchison and S. Garcia-Blanco and C. Hnatovsky and R. S. Taylor and F. Agulló-Rueda and A. J. Kellock and J. E. E. Baglin},
title = {Direct Observation of Waveguide Formation in KGd(WO_4)_2 by Low Dose H^+ Ion Implantation},
journal = {Appl. Phys. Lett.},
year = {2006},
volume = {89},
number = {11},
pages = {111116},
url = {http://dx.doi.org/10.1063/1.2340496},
doi = {10.1063/1.2340496}
}
|
| Molina P, Garc\ia BJ, Agulló-Rueda F, Ramirez MO and Bausá LE (2006), "Fabrication of domain inverted structures by direct electron bombardment in LiNbO_3 crystals and its characterization", Ferroelectrics. Vol. 334, pp. 343-348. |
| Abstract: Direct electron beam irradiation without static bias has been used to produce stable structures of ferroelectric domain inversion in LiNbO_3 and Nd^3+ doped LiNbO_3 single crystals. Large size cylinder-shaped domain-inverted regions, around 40 μm diametre and 500 μm thick, have been achieved in both types of crystals under the same experimental conditions. Raman spectroscopy has been used to analyze the effect of electron irradiation on the domain-inverted regions in the pure and Nd^3+ doped LiNbO_3 single crystals. The results evidence the structural equivalence of the reversed structures and thus, the suitability of this electron bombardment as a poling technique for high quality photonic devices. |
BibTeX:
@article{Molina06,
author = {Molina, P. and Garc\ia, B. J. and Agulló-Rueda, F. and Ramirez, M. O. and Bausá, L. E.},
title = {Fabrication of domain inverted structures by direct electron bombardment in LiNbO_3 crystals and its characterization},
journal = {Ferroelectrics},
year = {2006},
volume = {334},
pages = {343--348},
url = {https://doi.org/10.1080/00150190600689852},
doi = {10.1080/00150190600689852}
}
|
| Olivares J, Garc\ia G, Agulló-López F, Agulló-Rueda F, Soares JC and Kling A (2006), "Optical investigation of the propagation of the amorphous--crystalline boundary in ion-beam irradiated LiNbO_3", Nucl. Instrum. Meth. B. Vol. 242(1-2), pp. 534-537. |
| Abstract: The effects of high-energy silicon (5 MeV, 7.5 MeV and 30 MeV) irradiations have been optically investigated by the dark-mode m-lines technique. In all cases, an optically isotropic homogeneous layer is created after a certain critical fluence that depends on ion and energy. The structure of the layer has been investigated by micro-Raman spectroscopy and RBS/channeling. The inner boundary of the layer separating the amorphous and crystalline regions moves into the crystal on increasing fluence. The results are discussed based on the occurrence of a sharp threshold in the electronic stopping power leading to the formation of overlapped latent (amorphous) tracks. |
BibTeX:
@article{Olivares06nimb,
author = {J. Olivares and G. Garc\ia and F. Agulló-López and F. Agulló-Rueda and J. C. Soares and A. Kling},
title = {Optical investigation of the propagation of the amorphous--crystalline boundary in ion-beam irradiated LiNbO_3},
journal = {Nucl. Instrum. Meth. B},
year = {2006},
volume = {242},
number = {1--2},
pages = {534--537},
url = {http://dx.doi.org/10.1016/j.nimb.2005.08.205},
doi = {10.1016/j.nimb.2005.08.205}
}
|
| Rodenas A, Jaque D, Agulló-Rueda F and Kaminskii AA (2006), "Self-Activated Nd^3+:Ba_2NaNb_5O_12 optical superlattices: Micro-characterization and noncollinear laser light generation", Opt. Commun.. Vol. 262(2), pp. 220-223. |
| Abstract: Czochralsky grown Nd^3+-ion doped barium sodium niobate (Ba_2NaNb_5O_12, “banana”) optical super-lattices have been characterized by a combination of chemical etching, optical microscopy, micro-Raman and micro-photoluminescence experiments. The presence of ferroelectric domains, induced during growth process, is accompanied by a periodic modulation of Nd^3+-ion concentration as well as by a small lattice distortion. When Nd^3+-ion laser action at ≈ 1.06 μm is achieved under 0.808 μm laser diode pumping, the singularities of refractive index caused by opposed ferroelectric domains lead to non-collinear intra-cavity propagation. |
BibTeX:
@article{Rodenas06,
author = {A. Rodenas and D. Jaque and F. Agulló-Rueda and A. A. Kaminskii},
title = {Self-Activated Nd^3+:Ba_2NaNb_5O_12 optical superlattices: Micro-characterization and noncollinear laser light generation},
journal = {Opt. Commun.},
year = {2006},
volume = {262},
number = {2},
pages = {220--223},
url = {http://dx.doi.org/10.1016/j.optcom.2005.12.069},
doi = {10.1016/j.optcom.2005.12.069}
}
|
| Rodenas A, Jaque D, Torchia G, Mendez C, Arias I, Roso L, Moreno P and Agulló-Rueda F (2006), "Luminescence inhibition in femtosecond irradiated Nd:SBN crystals", J. Appl. Phys..
[BibTeX] |
BibTeX:
@article{Rodenas06b,
author = {Airan Rodenas and D. Jaque and Gustavo Torchia and Cruz Mendez and Isabel Arias and Luis Roso and Pedro Moreno and Fernando Agulló-Rueda},
title = {Luminescence inhibition in femtosecond irradiated Nd:SBN crystals},
journal = {J. Appl. Phys.},
year = {2006}
}
|
| Ródenas A, Sanz Garc\ia JA, Jaque D, Torchia G, Méndez C, Arias I, Roso L and Agulló-Rueda F (2006), "Optical investigation of femtosecond laser induced microstress in neodymium doped lithium niobate crystals", J. Appl. Phys.. Vol. 100(3), pp. 033521. |
| Abstract: The depth-resolved micromodification of single-crystalline femtosecond laser irradiated Nd^3+ doped MgO:LiNbO_3 crystals is investigated by means of micro-Raman and microluminescence experiments. We have found that a permanent tensile stress of the order of 2 GPa is induced in the vicinity of ablated volume as a consequence of the pressure-wave propagation due to the thermoelastic relaxation of the laser irradiated material. Microluminescence experiments have revealed that, as a consequence of the permanent laser induced microstress, a localized redshift of the 4F_3/2-->4I_9/2 luminescence band of Nd^3+ ions also takes place due to a crystal field modification. The analysis of Raman and fluorescence bandwidths indicates that a slight lattice disorder and densification is induced by femtosecond laser irradiation. |
BibTeX:
@article{Rodenas06c,
author = {Airán Ródenas and Sanz Garc\ia, Juan Antonio and Daniel Jaque and Gustavo Torchia and Cruz Méndez and Isabel Arias and Luis Roso and Fernando Agulló-Rueda},
title = {Optical investigation of femtosecond laser induced microstress in neodymium doped lithium niobate crystals},
journal = {J. Appl. Phys.},
year = {2006},
volume = {100},
number = {3},
pages = {033521},
url = {http://dx.doi.org/10.1063/1.2218991},
doi = {10.1063/1.2218991}
}
|
| Ródenas A, Jaque D, Torchia GA, Mendez C, Arias I, Roso L, Moreno P and Agulló-Rueda F (2006), "Femtosecond laser induced micromodifications in Nd:SBN crystals: Amorphization and luminescence inhibition", J. Appl. Phys.. Vol. 100(11), pp. 113517. AIP. |
| Abstract: We report on femtosecond laser modification of Nd:SBN crystals. Basic properties such as the ablation threshold have been obtained from the analysis of the ablation depths at different laser fluences. The induced micromodifications have been investigated by optical microscopy as well as by microphotoluminescence and micro-Raman experiments. We have found that in the vicinity of the ablated volume material amorphization can be induced along different directions. Furthermore, we have found that this material amorphization is accompanied by a strong inhibition of the Nd^3+ luminescence. The analysis of the spatial extension of the luminescence inhibition as a function of the laser fluence has been used to elucidate the origin of the femtosecond laser induced material amorphization. |
BibTeX:
@article{Rodenas06JAP,
author = {Ródenas, A. and Jaque, D. and Torchia, G. A. and Mendez, C. and Arias, I. and Roso, L. and Moreno, P. and Agulló-Rueda, F.},
title = {Femtosecond laser induced micromodifications in Nd:SBN crystals: Amorphization and luminescence inhibition},
journal = {J. Appl. Phys.},
publisher = {AIP},
year = {2006},
volume = {100},
number = {11},
pages = {113517},
url = {http://dx.doi.org/10.1063/1.2392721},
doi = {10.1063/1.2392721}
}
|
| Torres-Costa V, Mart\in-Palma RJ, Agulló-Rueda F and Mart\inez-Duart JM (2006), "Multicapas de silicio nanoestructurado para aplicaciones optoelectrónicas", In IX Congreso Nacional de Materiales, Vigo, 22--22 junio 2006. |
BibTeX:
@inproceedings{Torres-Costa06,
author = {Torres-Costa, V. and Mart\in-Palma, R. J. and Agulló-Rueda, F. and Mart\inez-Duart, J. M.},
title = {Multicapas de silicio nanoestructurado para aplicaciones optoelectrónicas},
booktitle = {IX Congreso Nacional de Materiales, Vigo, 22--22 junio 2006},
year = {2006},
url = {http://webs.uvigo.es/ixcnm/}
}
|
| Albella Mart\in JM, Mart\inez-Duart JM and Agulló-Rueda F (2005), "Fundamentos de microelectrónica, nanoelectrónica y fotónica" Madrid Pearson Educación. |
| Abstract: El contenido de Fundamentos de microelectrónica, nanoelectrónica y fotónica se refiere a los fundamentos f\isicos de los semiconductores y de los dispositivos electrónicos y optoelectrónicos. Habiendo numerosos tratados sobre Electrónica la mayor\ia de ellos, incluso los publicados en el extranjero, o bien están enfocados a la descripción de los aspectos más f\isicos (en cuyo caso el texto se refiere casi exclusivamente a la exposición de conceptos de la F\isica del Estado Sólido), o bien se dirigen al ingeniero de circuitos, basando entonces su contenido en la explicación de los diversos circuitos electrónicos, más o menos complejos, sin entrar con mucho detalle en los principios f\isicos. En este volumen se ha tratado de hacer un cuidadoso balance de ambos aspectos, intentando cubrir el entendimiento de los dispositivos básicos, desde la unión p-n de silicio hasta las modernas heterouniones y nanoestructuras, pasando por descripción de los circuitos electrónicos derivados de ellos utilizados en la electrónica analógica y digital. |
BibTeX:
@book{Albella05book,
author = {Albella Mart\in, José Mar\ia and Mart\inez-Duart, José Manuel and Agulló-Rueda, Fernando},
title = {Fundamentos de microelectrónica, nanoelectrónica y fotónica},
publisher = {Pearson Educación},
year = {2005},
url = {http://www.pearsoneducacion.com/}
}
|
| D\iaz R, Bisson L, Agulló-Rueda F, Lefdil MA and Rueda F (2005), "Effect of composition gradient on CuIn_3Te_5 single crystals properties, micro-Raman and infrared spectroscopies", Appl. Phys. A. Vol. 81(2), pp. 433-438. |
| Abstract: Several CuIn_3Te_5 single-crystal samples grown by the vertical Bridgman method have been studied. Changes in composition of the In/Cu atomic ratios in the 3.45--1.88 range have been detected along the ingots by X-ray energy-dispersive analysis. In the first-to-freeze region, Cu excess and In and Te depletions appear. From X-ray powder diffraction data we conclude that the crystals show the P-chalcopyrite-type structure, space group P42c, with lattice parameters a = 6.1713 Å and c = 12.329 Å, similar to that found in CuIn_3Se_5. The optical energy gaps, as determined by spectral ellipsometry, lie in the 1.83--1.93 eV range and change with composition. Micro-Raman spectra and infrared reflectance measurements confirm the presence of the crystallographic phase CuIn_3Te_5 and indicate a highly ordered Te sublattice and disordered Cu and In sublattices. Conduction types n and p are found, suggesting the possibility of intentional doping. The crystal density and gaps seem appropriate for their use in gamma-ray detectors. |
BibTeX:
@article{Diaz05,
author = {D\iaz, R. and Bisson, L. and Agulló-Rueda, F. and Lefdil, M. Abd and Rueda, F.},
title = {Effect of composition gradient on CuIn_3Te_5 single crystals properties, micro-Raman and infrared spectroscopies},
journal = {Appl. Phys. A},
year = {2005},
volume = {81},
number = {2},
pages = {433--438},
url = {http://dx.doi.org/10.1007/s00339-005-3245-x},
doi = {10.1007/s00339-005-3245-x}
}
|
| Olivares J, Garc\ia G, Agulló-López F, Agulló-Rueda F, Kling A and Soares JC (2005), "Generation of amorphous surface layers in LiNbO_3 by ion-beam irradiation: thresholding and boundary propagation", Appl. Phys. A. Vol. 81(7), pp. 1465-1469. |
| Abstract: The refractive-index profiles induced by high-energy (5 MeV, 7.5 MeV) silicon irradiation in LiNbO_3 have been systematically determined as a function of ion fluence in the range 10^13--10^15 cm^-2. At variance with irradiations at lower energies, an optically isotropic (‘amorphous’) homogeneous surface layer is generated whose thickness increases with fluence. These results have been associated with an electronic excitation mechanism. They are discussed in relation to the well-documented phenomenon of latent (amorphous) track generation under ion irradiation, requiring a threshold value S_e,th for the electronic stopping power S_e. Our optical data have yielded a value of ≈ 5 keV/nm for such a threshold, within the range reported by independent single-track measurements. The propagation of the amorphous boundary into the crystal during irradiation indicates that the threshold value decreases on increasing the fluence. Complementary Rutherford backscattering–channeling and micro-Raman (on samples irradiated at 30 MeV) experiments have been performed to monitor the induced structural changes. |
BibTeX:
@article{Olivares05,
author = {Olivares, J. and Garc\ia, G. and Agulló-López, F. and Agulló-Rueda, F. and Kling, A. and Soares, J. C.},
title = {Generation of amorphous surface layers in LiNbO_3 by ion-beam irradiation: thresholding and boundary propagation},
journal = {Appl. Phys. A},
year = {2005},
volume = {81},
number = {7},
pages = {1465--1469},
url = {http://dx.doi.org/10.1007/s00339-005-3237-x},
doi = {10.1007/s00339-005-3237-x}
}
|
| Torres-Costa V, Agulló-Rueda F, Mart\in-Palma RJ and Mart\inez-Duart JM (2005), "Porous silicon optical devices for sensing applications", Opt. Mater.. Vol. 27(5), pp. 1084-1087. |
| Abstract: Porous silicon (PS) has a great potential in a wide range of .elds due to its tuneable e.ective refractive index, which can be tai- lored through the precise control of the formation parameters. In particular, high/low porosity layer stacks result in optical multi- layer interference .lters, such as Bragg re.ectors and optical microcavities. In addition, due to its large internal surface, the optical properties of porous silicon are highly sensitive to the environmental conditions. Hence, a change in these conditions results in a shift of the optical spectrum of the PS multilayer structures. In the present work, the optical behavior of PS mirrors is studied, revealing good performance in the visible wavelength range, and showing a great sensitivity to di.erent liquids in.ltrated in the por- ous structure. Furthermore, optical microcavities are also demonstrated to .lter the photoluminescence emission of porous silicon, narrowing its spectral width and resulting in highly chromatical light emitting devices. These devices, along with the immobilization of biomolecules on the PS surface, will allow the development of low cost, high sensitivity optical biosensors. |
BibTeX:
@article{Torres-Costa05,
author = {Torres-Costa, V. and Agulló-Rueda, F. and Mart\in-Palma, R. J. and Mart\inez-Duart, J. M.},
title = {Porous silicon optical devices for sensing applications},
journal = {Opt. Mater.},
year = {2005},
volume = {27},
number = {5},
pages = {1084--1087},
url = {http://dx.doi.org/10.1016/j.optmat.2004.08.068},
doi = {10.1016/j.optmat.2004.08.068}
}
|
| Muñoz F, Agulló-Rueda F, Montagne L, Marchand R, Durán A and Pascual L (2004), "Structure and Properties of (25-x/2)Li_2O.(25-x/2)Na_2O.xPbO.50P_2O_5 Metaphosphate Glasses", J. Non-Cryst. Solids. Vol. 347, pp. 153-158. |
| Abstract: The structure of (25-x/2)Li_2O.(25-x/2)Na_2O.xPbO.50P_2O_5 phosphate glasses (0 ≤ x ≤ 50 mol has been investigated by Raman spectroscopy, and ^31P-MAS and ^207Pb-VOCS nuclear magnetic resonance. An increase in lead content affects the PO_4 tetrahedra network by weakening bonds between phosphorus and non-bridging oxygens. At low concentration, lead behaves as a modifier cation, with large coordination number. For higher PbO contents, a decrease in the coordination number of the Pb^2+ cations and an increase in the covalent character of the Pb--O bonds is observed. The changes in density and thermal properties of the glasses are explained through the structural evolution. The non-linear increase of the glass transition and dilatometric softening temperatures with PbO content is related to the non-linear variation of the PbO molar volume. This behavior is discussed in terms of the change in lead coordination when PbO is introduced in a mixed-alkali metaphosphate glass composition. |
BibTeX:
@article{Munoz04,
author = {Muñoz, Francisco and Agulló-Rueda, Fernando and Montagne, Lionel and Marchand, Roger and Durán, Alicia and Pascual, Luis},
title = {Structure and Properties of (25-x/2)Li_2O.(25-x/2)Na_2O.xPbO.50P_2O_5 Metaphosphate Glasses},
journal = {J. Non-Cryst. Solids},
year = {2004},
volume = {347},
pages = {153--158},
url = {http://dx.doi.org/10.1016/j.jnoncrysol.2004.07.086},
doi = {10.1016/j.jnoncrysol.2004.07.086}
}
|
| Olivares J, Garc\ia G, Agulló-López F, Agulló-Rueda F, Kling A and Soares JC (2004), "Electronic Energy Threshold Effects in the Production of LiNbO_3 Optical Waveguides by Ion Implantation", sent to Appl. Phys. Lett..
[BibTeX] |
BibTeX:
@article{Olivares04,
author = {Olivares, J. and Garc\ia, G. and Agulló-López, F. and Agulló-Rueda, F. and Kling, A. and Soares, J. C.},
title = {Electronic Energy Threshold Effects in the Production of LiNbO_3 Optical Waveguides by Ion Implantation},
journal = {sent to Appl. Phys. Lett.},
year = {2004}
}
|
| Romero JJ, Montoya E, Bausá LE, Agulló-Rueda F, Andreeta MRB and Hernandes AC (2004), "Multiwavelength Laser Action of Nd^3+:YAlO_3 Single Crystals Grown by the Laser Heated Pedestal Growth Method", Opt. Mater.. Vol. 24(4), pp. 643-650. |
| Abstract: We describe the growth of high quality transparent fibers of pure and Nd-doped YAlO_3 from unreacted pedestals (green rods) by the laser heated pedestal growth technique. The X-ray diffraction analysis shows that the fibers are monocrystalline, with a distorted Pnma perovskite structure and grow along direction (b axis). In this work, multi-wavelength laser action is demonstrated for these fibers in the two main laser channels of Nd^3+ ions. In the ^4F_3/2 → ^4I_11/2 laser transition, low threshold multi-wavelength laser emission is obtained at wavelengths of 1065, 1073 and 1081 nm. Additionally, for the first time in LHPG grown YAlO_3 fibers, laser action in the ^4F_3/2 → ^4I_13/2 transition is demonstrated at a wavelength of 1341 nm. |
BibTeX:
@article{Romero04b,
author = {J. J. Romero and E. Montoya and L. E. Bausá and F. Agulló-Rueda and M. R. B. Andreeta and A. C. Hernandes},
title = {Multiwavelength Laser Action of Nd^3+:YAlO_3 Single Crystals Grown by the Laser Heated Pedestal Growth Method},
journal = {Opt. Mater.},
year = {2004},
volume = {24},
number = {4},
pages = {643--650},
url = {http://dx.doi.org/10.1016/S0925-3467(03)00179-4},
doi = {10.1016/S0925-3467(03)00179-4}
}
|
| Agulló-Rueda F and Serna R (2003), "Métodos ópticos", In Láminas delgadas y recubrimientos. Madrid , pp. 376-400. Consejo Superior de Investigaciones Cient\ificas. |
| Abstract: Los métodos ópticos de caracterización han sido desde el principio fundamentales en el estudio de la materia y en particular de las capas delgadas. Estos métodos son en general no destructivos y relativamente baratos, pues en el caso más sencillo basta dirigir un haz de luz sobre la muestra y estudiar su respuesta óptica. La información obtenida es muy amplia y no sólo se limita a las propiedades ópticas, sino que se puede obtener el espesor de las muestras, su rugosidad, composición qu\imica, defectos e incluso la estructura atómica y electrónica. As\i los métodos ópticos fueron claves en el desarrollo de la astronom\ia y de la teor\ia cuántica. En la primera parte de este cap\itulo se repasan los fundamentos de la interacción luz-materia. En la segunda parte se introducen los metódos ópticos y espectroscópicos de análisis más relevantes (reflectancia, transmitancia, elipsometr\ia, fluorescencia y espectroscop\ias vibracionales). |
BibTeX:
@incollection{Agullo-Rueda03,
author = {Agulló-Rueda, F. and Serna, R.},
editor = {Albella, José Mar\ia},
title = {Métodos ópticos},
booktitle = {Láminas delgadas y recubrimientos},
publisher = {Consejo Superior de Investigaciones Cient\ificas},
year = {2003},
pages = {376--400},
url = {http://www.csic.es/}
}
|
| Agulló-Rueda F and Albella JM (2003), "Aplicaciones de capas semiconductoras en microelectrónica y fotónica", In Láminas delgadas y recubrimientos. Madrid , pp. 634-659. Consejo Superior de Investigaciones Cient\ificas. |
| Abstract: La fabricación de los llamados dispositivos `optoelectrónicos' requiere el concurso de técnicas deposición de los materiales en capa delagada en condiciones muy estrictas en lo que se refiere a la pureza del material, homgeneidad del depósito, composición, espesor de la capa depositada, etc. Todo ello, unido a la necesidad de integrar los componentes de un circuito en áreas muy pequeñas, de dimensiones micrométricas, ha dado lugar al desarrollo de una nueva tecnolog\ia de microelectrónica que incluye tanto las técnicas de depositición como las de ataque y tratamiento superficial en regiones muy precisas de un substrato semiconductor. En este cap\itulo se hace un repaso de los aspectos fundamentales de esta tecnológia sobre todo en lo que se refiere a los materiales y procesos empleados en la deposición de las diferentes capas que componen los dispositivos optoelectrónicos. |
BibTeX:
@incollection{Agullo-Rueda03b,
author = {Agulló-Rueda, F. and Albella, J. M.},
editor = {Albella, José Mar\ia},
title = {Aplicaciones de capas semiconductoras en microelectrónica y fotónica},
booktitle = {Láminas delgadas y recubrimientos},
publisher = {Consejo Superior de Investigaciones Cient\ificas},
year = {2003},
pages = {634--659},
url = {http://editorial.csic.es/publicaciones/libros/10949/978-84-00-08166-9/laminas-delgadas-y-recubrimientos-preparacion-prop.html}
}
|
| Arias D, Sefrioui Z, Loos GD, Agulló-Rueda F, Garcia-Barriocanal J, Leon C and Santamaria J (2003), "Pair Breaking by Chain Oxygen Disorder in Light-Ion Irradiated YBa_2Cu_3O_x Thin Films", Phys. Rev. B. Vol. 68, pp. 94515. |
| Abstract: We report on the effect of oxygen disorder in the CuO chains on the superconducting properties of oxygen depleted YBa_2Cu_3O_x (YBCO). While moderate disorder, induced thermally, depresses the critical temperature as a result of a reduced carrier concentration, strong oxygen disorder and chain fragmentation induced by low energy (80 keV) He^+ irradiation suppresses the critical temperature beyond the values expected from the reduction of the carrier density. This provides an experimental evidence of pair breaking by chain disorder and outlines the importance of chain states in the pairing mechanism in the YBCO family. |
BibTeX:
@article{Arias03,
author = {Arias, D. and Sefrioui, Z. and Loos, G. D. and Agulló-Rueda, F. and Garcia-Barriocanal, J. and Leon, C. and Santamaria, J.},
title = {Pair Breaking by Chain Oxygen Disorder in Light-Ion Irradiated YBa_2Cu_3O_x Thin Films},
journal = {Phys. Rev. B},
year = {2003},
volume = {68},
pages = {94515},
url = {http://dx.doi.org/10.1103/PhysRevB.68.094515},
doi = {10.1103/PhysRevB.68.094515}
}
|
| Ojeda F, Cuerno R, Salvarezza R, Agulló-Rueda F and Vázquez L (2003), "Modeling Heterogeneity and Memory Effects on the Kinetic Roughening of Silica Films Grown by Chemical Vapor Deposition", Phys. Rev. B. Vol. 67, pp. 245416. |
| Abstract: We present discrete and continuum models to describe previous experiments on growth of chemical vapor deposited silica films at 611 K and 723 K [F. Ojeda et al., Phys. Rev. Lett. 84, 3125 (2000)]. Silica films deposited at 723 K show larger surface roughness already from the early stages of growth, a fact that was not explained by a previously proposed phenomenological stochastic equation for the interface height. This larger surface roughness and the concomitant development of higher local slopes seem to be correlated with the Kardar-Parisi-Zhang asymptotic scaling observed for the high-temperature conditions. Here, we explain these features on the basis of surface heterogeneity and short-range memory effects, which are assessed for our experimental system through spectroscopic measurements. By incorporating these effects into a random deposition model and related Langevin equations with correlated noise, we are able to account for the full set of experimental observations. |
BibTeX:
@article{Ojeda03,
author = {Ojeda, Fernando and Cuerno, Rodolfo and Salvarezza, Roberto and Agulló-Rueda, Fernando and Vázquez, Luis},
title = {Modeling Heterogeneity and Memory Effects on the Kinetic Roughening of Silica Films Grown by Chemical Vapor Deposition},
journal = {Phys. Rev. B},
year = {2003},
volume = {67},
pages = {245416},
url = {http://dx.doi.org/10.1103/PhysRevB.67.245416},
doi = {10.1103/PhysRevB.67.245416}
}
|
| Pascual A, Manotas S, Mart\in P, Fernández JF, Agulló-Rueda F and Sánchez CR (2003), "Stability of PL and Surface Coverage of n Type Porous Silicon", Phys. Stat. Sol. (a). Vol. 197(2), pp. 467-470. |
| Abstract: Experimental results presented in this paper on photoluminescence (PL) and thermal desorption spectroscopy of n-type porous silicon (PS) are consistent with the extinction of the PL emission being due to the creation of free bonds at the surface of the porous layer crystallites. Desorption of hydrogen and SiH_4 have been thoroughly investigated. Extinction of PL has been studied after heating the samples in high vacuum and in an Ar atmosphere |
BibTeX:
@article{Pascual03,
author = {Pascual, A. and Manotas, S. and Mart\in, P. and Fernández, J. F. and Agulló-Rueda, F. and Sánchez, C. R.},
title = {Stability of PL and Surface Coverage of n Type Porous Silicon},
journal = {Phys. Stat. Sol. (a)},
year = {2003},
volume = {197},
number = {2},
pages = {467--470},
url = {http://dx.doi.org/10.1002/pssa.200306546},
doi = {10.1002/pssa.200306546}
}
|
| Serna R and Agulló-Rueda F (2003), "Propiedades ópticas de capas delgadas. Aplicaciones", In Láminas delgadas y recubrimientos. Madrid , pp. 662-684. Consejo Superior de Investigaciones Cient\ificas. |
| Abstract: En los últimos años se ha conseguido un gran avance en la tecnolog\ia de capas delgadas para aplicaciones ópticas. Esto es debido a que las aplicaciones tecnológicas han ido aumentado el nivel de exigencia en lo que se refiere a la calidad y prestaciones de las capas delgadas. Es interesante reseñar que han sido estas aplicaciones las que han impulsado al campo a un constante desarrollo, especialmente las relacionadas con los láseres. En el siglo XXI los nuevos desarrollos en telecomunicaciones ópticas, óptica integrada, y las aplicaciones en el espacio y tecnolog\ia militar sin duda impondrán nuevos retos. En este cap\itulo repasaremos las propiedades ópticas de los sistemas formados por múltiples capas, y mostraremos algunas de las aplicaciones que consideramos más relevantes. |
BibTeX:
@incollection{Serna03,
author = {Serna, R. and Agulló-Rueda, F.},
editor = {Albella, José Mar\ia},
title = {Propiedades ópticas de capas delgadas. Aplicaciones},
booktitle = {Láminas delgadas y recubrimientos},
publisher = {Consejo Superior de Investigaciones Cient\ificas},
year = {2003},
pages = {662--684},
url = {http://www.csic.es/}
}
|
| Andreeta ERM, Rodrigues JA, Andreeta MRB, Agulló-Rueda F and Hernandes AC (2002), "Directional Solidification of the Al_2O_3/GdAlO_3 Eutectic by Laser Melting Technique", Cerâmica. Vol. 48(305), pp. 29-33. |
| Abstract: Pore-free eutectic fibers of Al_2O_3/GdAlO_3 were produced by the laser melting technique named LHPG. The chinese script microstructure was observed using scanning electron microscopy. Fibrous pattern could be found in some of the samples. MicroRaman spectroscopy could index the eutectic phases and showed the continuity of the fibrous GdAlO_3 when compared to the chinese script pattern. Three points bending measurements resulted in values of modulus of rupture varying from 490 MPa to 1316 MPa. |
BibTeX:
@article{Andreeta02,
author = {Andreeta, E. R. M. and Rodrigues, J. A. and Andreeta, M. R. B. and Agulló-Rueda, F. and Hernandes, A. C.},
title = {Directional Solidification of the Al_2O_3/GdAlO_3 Eutectic by Laser Melting Technique},
journal = {Cerâmica},
year = {2002},
volume = {48},
number = {305},
pages = {29--33},
url = {https://doi.org/10.1590/S0366-69132002000100007},
doi = {10.1590/S0366-69132002000100007}
}
|
| Andreeta MRB, Caraschi LC, Agulló-Rueda F and Hernandes AC (2002), "Periodic Doping in Single Crystal Fibers Grown by Laser-Heated Pedestal Growth Technique", J. Cryst. Growth. Vol. 242(3-4), pp. 395-399. |
| Abstract: The height of the molten zone was modulated during single crystal fiber pulling by the laser-heated pedestal growth technique to create a periodically doped fiber. Different frequencies, in the order of 10^-3 Hz, were used to modulate the molten zone during the growth of LaAlO_3:Cr^3+ fibers, a material model. We demonstrated that the axial Cr^3+ distribution varied periodically along the length of the fiber at the same frequency as the molten zone oscillations. A dopant distribution model, based on mass conservation, was successfully applied to predict the axial Cr^3+ concentration profile. The effective segregation coefficient (k_eff) of the LaAlO_3:Cr^3+ was determined to be 4.6 (without molten zone oscillation). The growth temperature was (2340 ± 10)^circC and growth was carried out in an air atmosphere. The fiber/pedestal-pulling ratio was equal to 1.0. Transparent fibers 450 μ m in diameter and 3 cm in length were obtained. |
BibTeX:
@article{Andreeta02b,
author = {Andreeta, M. R. B. and Caraschi, L. C. and Agulló-Rueda, F. and Hernandes, A. C.},
title = {Periodic Doping in Single Crystal Fibers Grown by Laser-Heated Pedestal Growth Technique},
journal = {J. Cryst. Growth},
year = {2002},
volume = {242},
number = {3--4},
pages = {395--399},
url = {http://dx.doi.org/10.1016/S0022-0248(02)01415-X},
doi = {10.1016/S0022-0248(02)01415-X}
}
|
| Dickerson JH, Mendez EE, Allerman AA, Manotas S, Agulló-Rueda F and Pecharromán C (2002), "Electric Field Enhancement of the Rabi Splitting in a Superlattice-Microcavity System", Physica E. Vol. 13(2-4), pp. 398-402. |
| Abstract: We have observed a large coupling between the photonic mode of a microcavity and Stark-localized excitons from a superlattice embedded in it. The coupling is signi cantly stronger than in comparable microcavities that contain quantum 11 wells solely at the antinodes. The large density of exciton states in a superlattice and their large binding energy, once they are con ned by an electric eld, explain this enhancement. |
BibTeX:
@article{Dickerson02,
author = {Dickerson, J. H. and Mendez, E. E. and Allerman, A. A. and Manotas, S. and Agulló-Rueda, F. and Pecharromán, C.},
title = {Electric Field Enhancement of the Rabi Splitting in a Superlattice-Microcavity System},
journal = {Physica E},
year = {2002},
volume = {13},
number = {2--4},
pages = {398--402},
url = {http://dx.doi.org/10.1016/S1386-9477(02)00149-2},
doi = {10.1016/S1386-9477(02)00149-2}
}
|
| Gago R, Jiménez I, Agulló-Rueda F, Albella JM, Czigány Z and Hultman L (2002), "Transition from Amorphous Boron Carbide to Hexagonal Boron Carbon Nitride Thin Films Induced by Nitrogen Ion Assistance", J. Appl. Phys.. Vol. 92(9), pp. 5177-5182. |
| Abstract: Boron carbon nitride films (BCN) were grown by B_4C evaporation under concurrent N_2 ion beam assistance. The films were characterized by x-ray absorption near-edge spectroscopy, infrared and Raman spectroscopies, and high-resolution transmission electron microscopy. The bonding structure and film composition correlate with the momentum transfer per incoming atom during deposition. As the momentum transfer is increased, the film structure evolves from an amorphous boron carbide network towards a hexagonal ternary compound (h--BCN) with standing basal planes. The growth of h--BCN takes place for momentum transfer in the window between 80 and 250 (eV × amu)^1/2 . The characteristic vibrational features of the h--BCN compounds have also been studied. Finally, the solubility limit of carbon in the hexagonal BN structure, under the working conditions of this article, is found to be ≈15 at. %. |
BibTeX:
@article{Gago02,
author = {Gago, R. and Jiménez, I. and Agulló-Rueda, F. and Albella, J. M. and Czigány, Zs. and Hultman, L.},
title = {Transition from Amorphous Boron Carbide to Hexagonal Boron Carbon Nitride Thin Films Induced by Nitrogen Ion Assistance},
journal = {J. Appl. Phys.},
year = {2002},
volume = {92},
number = {9},
pages = {5177--5182},
url = {http://dx.doi.org/10.1063/1.1512317},
doi = {10.1063/1.1512317}
}
|
| Pascual A, Fernández JF, Sánchez CR, Manotas S and Agulló-Rueda F (2002), "Structural Characteristics of p-Type Porous Silicon and their Relation to the Nucleation and Growth of Pores", J. Porous Mater.. Vol. 9(1), pp. 57-66. |
| Abstract: The influence of the anodization time on some structural characteristics (dissolved mass, maximum porous layer thickness, porosity, crystallite size, etc.) of p-type porous silicon has been investigated. It is shown that chemical dissolution of the porous layer during the anodization must be taken into account in order to correct some of the experimental data. Measurements of the anode potential have allowed to distinguish an early stage of the porous layer formation due to nucleation of pores. Equations based on pore nucleation and growth processes explain well the evolution of the maximum layer thickness with anodization time. |
BibTeX:
@article{Pascual01,
author = {Pascual, A. and Fernández, J. F. and Sánchez, C. R. and Manotas, S. and Agulló-Rueda, F.},
title = {Structural Characteristics of p-Type Porous Silicon and their Relation to the Nucleation and Growth of Pores},
journal = {J. Porous Mater.},
year = {2002},
volume = {9},
number = {1},
pages = {57--66},
url = {http://dx.doi.org/10.1023/A:1014312107140},
doi = {10.1023/A:1014312107140}
}
|
| Callejo D, Manotas S, Serrano MD, Bermúdez V, Agulló-Rueda F and Diéguez E (2001), "Compositional Study of LiNbO_3 Thin Films Grown by Liquid Phase Epitaxy", J. Crystal Growth. Vol. 226(4), pp. 488-492. |
| Abstract: Lithium niobate (LN) films have been obtained on pure congruent single-domain LN substrates by the liquid phase epitaxy technique. Li-rich flux of LiVO_3 has been used. The optimum temperature for the film preparation has been found to be 860^circC. Raman and photoluminescence microspectroscopy were used to analyse the Li/Nb ratio, which decreases along the film depth, and the vanadium concentration, which increases along the film depth. |
BibTeX:
@article{Callejo01,
author = {Callejo, D. and Manotas, S. and Serrano, M. D. and Bermúdez, V. and Agulló-Rueda, F. and Diéguez, E.},
title = {Compositional Study of LiNbO_3 Thin Films Grown by Liquid Phase Epitaxy},
journal = {J. Crystal Growth},
year = {2001},
volume = {226},
number = {4},
pages = {488--492},
url = {http://dx.doi.org/10.1016/S0022-0248(01)01405-1},
doi = {10.1016/S0022-0248(01)01405-1}
}
|
| Dickerson JH, Mendez EE, Allerman AA, Manotas S, Agulló-Rueda F and Pecharromán C (2001), "Enhancement of Rabi Splitting in a Microcavity with an Embedded Superlattice", Phys. Rev. B. Vol. 64, pp. 155302. |
| Abstract: We have observed a large coupling between the excitonic and photonic modes of an AlAs/AlGaAs microcavity filled with an 84 20 Å GaAs/AlGaAs superlattice. Reflectivity measurements on the coupled cavity-superlattice system in the presence of a moderate electric field yielded Rabi splittings of 8.5 meV at T = 293 K and 9.5 meV at T = 238 K. This splitting is almost 50% larger than that found in comparable microcavities with quantum wells placed at the antinodes only. We explain the enhancement by the larger density of optical absorbers in the superlattice, combined with the quasi-two-dimensional binding energy of field-localized excitons. |
BibTeX:
@article{Dickerson01,
author = {J. H. Dickerson and E. E. Mendez and A. A. Allerman and S. Manotas and F. Agulló-Rueda and C. Pecharromán},
title = {Enhancement of Rabi Splitting in a Microcavity with an Embedded Superlattice},
journal = {Phys. Rev. B},
year = {2001},
volume = {64},
pages = {155302},
url = {http://dx.doi.org/10.1103/PhysRevB.64.155302},
doi = {10.1103/PhysRevB.64.155302}
}
|
| Gago R, Jiménez I, Cáceres D, Agulló-Rueda F, Sajavaara T, Albella JM, Climent-Font A, Vergara I, Räisänen J and Rauhala E (2001), "Hardening mechanisms in graphitic carbon nitride films grown with N_2/Ar ion assistance", Chem. Mater.. Vol. 13(1), pp. 129-135. |
| Abstract: Amorphous carbon nitride films have been grown by ion beam assisted deposition (IBAD) under different process conditions. The films were found to be graphitic, with π bonds between C and N atoms and a [N]/[C] ratio below 0.3. There is a relationship between the contribution of electrons from C and N atoms to the π bonds and the mechanical properties of the films. This is consistent with the arrangement of the basal planes, the softer films consisting in the pileup of weakly interacting graphitic planes and the harder films consisting in a superstructure of interconnected and corrugated basal planes. Aiming toward the synthesis of nongraphitic hard phases, we have studied the bombardment with mixtures of nitrogen/argon ions to enhance momentum transfer in the collisions. The hardest films are obtained when using a single type of ions. The hardness is reduced in the case of the N_2/Ar mixture, indicating competitive mechanisms of cross-linking of basal planes. |
BibTeX:
@article{Gago01,
author = {Gago, R. and Jiménez, I. and Cáceres, D. and Agulló-Rueda, F. and Sajavaara, T. and Albella, J. M. and Climent-Font, A. and Vergara, I. and Räisänen, J. and Rauhala, E.},
title = {Hardening mechanisms in graphitic carbon nitride films grown with N_2/Ar ion assistance},
journal = {Chem. Mater.},
year = {2001},
volume = {13},
number = {1},
pages = {129--135},
url = {http://dx.doi.org/10.1021/cm001160c},
doi = {10.1021/cm001160c}
}
|
| Kaminskii AA, Bagayev SN, Ueda K-I, Eichler HJ, Garcia-Sole J, Jaque D, Romero JJ, Fernandez J, Balda R, Butashin AV and Agulló-Rueda F (2001), "Multiple Stokes and Anti-Stokes Picosecond Generation, cw Laser Action at Wavelengths of Two Stimulated-Emission Channels ^4F_3/2 → ^4I_11/2 and ^4F_3/2 → ^4I_13/2, and Nanosecond Self-SRS Lasing in Undoped and Nd^3+-Doped Tetragonal PbMoO_4 Crystals", Laser Phys.., In Proceedings of the Third International Symposium on Modern Problems of Laser Physics (MPLP-2000), Novosibirsk, Russia, July 2--7, 2000. Vol. 11(10), pp. 1142-1146. |
BibTeX:
@article{Kaminskii01,
author = {Kaminskii, A. A. and Bagayev, S. N. and Ueda, K.-I. and Eichler, H. J. and Garcia-Sole, J. and Jaque, D. and Romero, J. J. and Fernandez, J. and Balda, R. and Butashin, A. V. and Agulló-Rueda, F.},
editor = {Bagayev, Sergey N.},
title = {Multiple Stokes and Anti-Stokes Picosecond Generation, cw Laser Action at Wavelengths of Two Stimulated-Emission Channels ^4F_3/2 → ^4I_11/2 and ^4F_3/2 → ^4I_13/2, and Nanosecond Self-SRS Lasing in Undoped and Nd^3+-Doped Tetragonal PbMoO_4 Crystals},
booktitle = {Proceedings of the Third International Symposium on Modern Problems of Laser Physics (MPLP-2000), Novosibirsk, Russia, July 2--7, 2000},
journal = {Laser Phys.},
year = {2001},
volume = {11},
number = {10},
pages = {1142--1146},
url = {https://www.elibrary.ru/item.asp?id=13371804}
}
|
| Manotas S, Agulló-Rueda F, Moreno JD, Ben-Hander F and Mart\inez-Duart JM (2001), "Lattice-Mismatch Induced Stress in Porous Silicon Films", Thin Solid Films. Vol. 401(1-2), pp. 306-309. |
| Abstract: We have studied the stress in porous silicon films with different porosities at the interface with the substrate. Micro-Raman spectra were measured along a cleaved cross section to sample different layer depths. Each spectrum was fit to the phonon confinement model, with the bulk phonon frequency as a free parameter to remove phonon confinement effects. At the interface this frequency increases sharply, indicating a compressive stress on the porous silicon pillars. The stress is due to the lattice mismatch, measured by x-ray diffraction, between the porous film and the bulk silicon substrate. For porosities between 50% and 85% the stress and the lattice mismatch vary, respectively, between 4 and 10 kbar, and between 2.9 × 10^-3 and 3.5 × 10^-3. Finally, from the dependence of stress on the lattice mismatch we obtain a microscopic Young's modulus of 156 GPa. This magnitude, mostly dependent on atomic bonding, is close to the bulk silicon value and much larger than the macroscopic modulus, strongly dependent on the porous structure, reported in the literature. |
BibTeX:
@article{Manotas01,
author = {Manotas, S. and Agulló-Rueda, F. and Moreno, J. D. and Ben-Hander, F. and Mart\inez-Duart, J. M.},
title = {Lattice-Mismatch Induced Stress in Porous Silicon Films},
journal = {Thin Solid Films},
year = {2001},
volume = {401},
number = {1--2},
pages = {306--309},
url = {http://dx.doi.org/10.1016/S0040-6090(01)01641-8},
doi = {10.1016/S0040-6090(01)01641-8}
}
|
| Manotas Cabeza S (2001), "Microespectroscop\ia de materiales optoelectrónicos: silicio poroso y microcavidades de GaAs/AlGaAs". Thesis at: Universidad Autónoma de Madrid. Departamento de F\isica de Materiales. |
| Abstract: En este trabajo se estudian por microespeciroscopia Raman y microfotoluminiscencia dos materiales semiconductores nanoestructurados con interes en optoelectcónica: el silicio poroso y las microcavidades de GaAs/- AlGaAs. En el silicio poroso, se estudia el aumento de temperatura que produce el calentamiento inducido por el láser, la estabilidad de la fotoluminiscencia en función de la temperatura, la tensión mecánica en la región cercana a la intercara con el sustnito de silicio, y las propiedades de multicapas. En las microcavidades, los estudios en una sección ttansversal permiten caracterizar cada capa. Por último, medidas en la dirección de crecimiento estudian los efectos de acoplamiento presentes en el interior de la cavidad, comparando el desdoblamiento Rabi obtenido para una cavidad formada por pozos cuinticos aislados y una superred, respectivamente We have characterized two nanostructured semiconductor materials interesting in optoelectronics using micro-Ramm spectroscopy and microphotoluminescence: porous silicon and GaAsíAlGaAs microcavities. In porous silicon, we have studied the temperature rise due to laser heating effects, the photoluminescence stability as a function of the temperature, the mechanical stress near the interface with silicon substrate, and the propetties of multilayers. in microcavities, cross-section studies characterize each layer. At the end, measurements in the growth direction shidy the coupling effects in the cavim comparíng Rabi spiitting for a cavity with isolated quantum welis and a superlattice, respectively. |
BibTeX:
@phdthesis{ManotasCabeza2002PhD,
author = {Manotas Cabeza, Sonsoles},
title = {Microespectroscop\ia de materiales optoelectrónicos: silicio poroso y microcavidades de GaAs/AlGaAs},
school = {Universidad Autónoma de Madrid. Departamento de F\isica de Materiales},
year = {2001},
url = {http://hdl.handle.net/10486/672268}
}
|
| Montoya E, Agulló-Rueda F, Manotas S, Garc\ia-Solé J and Bausá LE (2001), "Electron-Phonon Coupling in Yb^3+:LiNbO_3 Laser Crystal", J. Lumin.., December, 2001. Vol. 94--95, pp. 701-705. |
| Abstract: Electron-phonon coupling in Yb^3+:LiNbO_3 is studied by comparing the optical (absorption and emission) low-temperature spectra with the room temperature Raman spectrum of undoped LiNbO_3. As a result, the whole vibrational structure of the optical spectra can be explained by a coupling of the optical phonons of LiNbO_3 and electronic transitions of Yb^3+. |
BibTeX:
@article{Montoya01,
author = {Montoya, E. and Agulló-Rueda, F. and Manotas, S. and Garc\ia-Solé, J. and Bausá, L. E.},
title = {Electron-Phonon Coupling in Yb^3+:LiNbO_3 Laser Crystal},
journal = {J. Lumin.},
year = {2001},
volume = {94--95},
pages = {701--705},
url = {http://dx.doi.org/10.1016/S0022-2313(01)00350-7},
doi = {10.1016/S0022-2313(01)00350-7}
}
|
| Agulló-Rueda F, Mendez EE, Bojarczuk B and Guha S (2000), "Raman Spectroscopy of Wurtzite InN Films Grown on Si", Solid State Comm.. Vol. 115(1), pp. 19-21. |
| Abstract: We have used Raman spectroscopy to study indium nitride thin films grown by molecular beam epitaxy on (111) silicon substrates at temperatures between 450 and 550^circC. The Raman spectra show well defined peaks at 443, 475, 491 and 591 cm^-1, which correspond to the A_1(TO), E_1(TO), E_2^high, and A_1(LO) phonons of the wurtzite structure, respectively. In backscattering normal to the surface the A_1(TO) and E_1(TO) peaks are very weak, indicating that the films grow along the hexagonal c-axis. For a growth temperature of 500^circC, the E_2^high peak has a full width at half maximum of 7 cm^-1, which is comparable to the value reported for wurtzite InN films grown on sapphire. |
BibTeX:
@article{Agullo-Rueda00,
author = {Agulló-Rueda, F. and Mendez, E. E. and Bojarczuk, B. and Guha, S.},
title = {Raman Spectroscopy of Wurtzite InN Films Grown on Si},
journal = {Solid State Comm.},
year = {2000},
volume = {115},
number = {1},
pages = {19--21},
url = {http://dx.doi.org/10.1016/S0038-1098(00)00132-0},
doi = {10.1016/S0038-1098(00)00132-0}
}
|
| Agulló-Rueda F (2000), "Espectroscop\ia Raman", In Ciencia e Ingenier\ia de la Superficie Metálica. Madrid , pp. 561-572. Consejo Superior de Investigaciones Cient\ificas. |
| Abstract: Este cap\itulo es una introducción a la espectroscop\ia Raman. Con esta técnica óptica se estudian de forma no destructiva compuestos en estado gaseoso, l\iquido o sólido. En los materiales permite caracterizar la estructura, el grado de cristalinidad, la composición, la tensión mecánica, la temperatura, etc. En el caso de los metales se emplea principalmente para caracterizar recubrimientos y depósitos de corrosión sobre la superficie metálica. |
BibTeX:
@incollection{Agullo-Rueda00b,
author = {Agulló-Rueda, Fernando},
editor = {Vázquez, A. J. and de Damborenea, J. J.},
title = {Espectroscop\ia Raman},
booktitle = {Ciencia e Ingenier\ia de la Superficie Metálica},
publisher = {Consejo Superior de Investigaciones Cient\ificas},
year = {2000},
pages = {561--572},
url = {http://editorial.csic.es/publicaciones/libros/4622/978-84-00-07920-8/ciencia-e-ingenieria-de-la-superficie-de-los-mater.html}
}
|
| Bañares MA, Cardoso JH, Agulló-Rueda F, Correa-Bueno JM and Fierro. JLG (2000), "Dynamic states of V-oxide species: reducibility and performance for methane oxidation on V_2O_5/SiO_2 catalysts as a function of coverage", Catal. Lett.. Vol. 64(2-4), pp. 191-196. |
| Abstract: Temperature-programmed in situ Raman spectroscopy is used to understand the effect of surface vanadia coverage on the structure, reducibility and performance for the oxidation of methane on V_2O_5/SiO_2 catalysts. The vanadia coverage on silica has no effect on its structure below its dispersion-limit loading (monolayer coverage); however, the interactions among surface vanadia species under reducing conditions become increasingly important. This interaction appears to operate through the sharing of oxygen sites facilitating the reduction, but it does not alter the total reducibility. The probability for this interaction to take place increases with vanadium oxide surface coverage. It is therefore expected that under reaction conditions the catalyst with higher vanadia coverage would have a greater capacity to release oxygen. This would increase the activity per vanadium site. |
BibTeX:
@article{Banares00,
author = {Bañares, M. A. and Cardoso, J. H. and Agulló-Rueda, F. and Correa-Bueno, J. M. and Fierro., J. L. G.},
title = {Dynamic states of V-oxide species: reducibility and performance for methane oxidation on V_2O_5/SiO_2 catalysts as a function of coverage},
journal = {Catal. Lett.},
year = {2000},
volume = {64},
number = {2--4},
pages = {191--196},
url = {http://dx.doi.org/10.1023/A:1019043205270},
doi = {10.1023/A:1019043205270}
}
|
| Bermúdez V, Callejo D, Caccavale F, Segato F, Agulló-Rueda F and Diéguez E (2000), "On the Compositional Nature of Bulk Doped Periodic Poled Lithium Niobate Crystals", Solid State Comm.. Vol. 114(10), pp. 555-559. |
| Abstract: The compositional nature of the Erbium, Neodymium and Yttrium bulk doped periodic poled lithium niobate crystals obtained by the off-centered Czochralski technique has been studied. It has been observed that, in all cases, the impurity concentration is constant along the periodic domain structure. Moreover, it is shown that there exists a periodical variation in the Nb concentration, which is directly related with an inversion in the Li/Nb ratio along the periodic domain structure. The magnitude of the Nb variation seems to depend on the nature of the dopant and its position in the lithium niobate lattice, together with the value of the segregation coefficient of the impurity and the shape of the solidliquid interface during growth. |
BibTeX:
@article{Bermudez00,
author = {V. Bermúdez and D. Callejo and F. Caccavale and F. Segato and F. Agulló-Rueda and E. Diéguez},
title = {On the Compositional Nature of Bulk Doped Periodic Poled Lithium Niobate Crystals},
journal = {Solid State Comm.},
year = {2000},
volume = {114},
number = {10},
pages = {555--559},
url = {http://dx.doi.org/10.1016/S0038-1098(00)00086-7},
doi = {10.1016/S0038-1098(00)00086-7}
}
|
| de las Heras C and Agulló-Rueda F (2000), "Raman Spectroscopy of NiSe_2 and NiS_2-xSe_x (0 < x < 2) Thin Films", J. Phys. C: Condens. Matter. Vol. 12(24), pp. 5317-5324. |
| Abstract: The Raman spectra of NiS_2-xSe_x (0 < x < 2) polycrystalline thin films have been measured for the first time in the whole x range and for NiSe_2. The NiSe_2 spectrum is qualitatively similar to the spectrum of NiS_2, but all frequencies are shifted to lower energies. The shift has been analysed in terms of the increment of the anion mass and the lattice expansion. Peaks in the Raman spectrum of the NiS_2-xSe_x alloy can be assigned to stretching and rotational modes of the S-S, Se-Se and S-Se pairs. The stretching vibration of the S-Se pairs shifts almost linearly from 400 cm^-1 for NiS_2 to 330 cm^-1 for NiSe_2. There is an accidental degeneracy between the S-S stretching and Se-Se libration frequencies. The relative Raman intensities fit well with a random occupation of the anion sites by S and Se atoms, and different scattering cross sections. |
BibTeX:
@article{Heras00,
author = {de las Heras, C. and Agulló-Rueda, F.},
title = {Raman Spectroscopy of NiSe_2 and NiS_2-xSe_x (0 < x < 2) Thin Films},
journal = {J. Phys. C: Condens. Matter},
year = {2000},
volume = {12},
number = {24},
pages = {5317--5324},
url = {http://dx.doi.org/10.1088/0953-8984/12/24/320},
doi = {10.1088/0953-8984/12/24/320}
}
|
| Kaminskii AA, Bagayev SN, Ueda K-I, Eichler HJ, Garcia-Sole J, Jaque D, Romero JJ, Fernandez J, Balda R, Butashin AV and Agulló-Rueda F (2000), "New Laser and (3)-Nonlinear Properties of PbMoO_4:Nd^3+: CW Stimulated Emission at 1.0594 and 1.335 μM, High-Order Picosecond Raman Generation, and Nanosecond Self-SRS Lasing", In Proceedings of the Third International Symposium on Modern Problems of Laser Physics (MPLP-2000). Akademgorodok, Novosibirsk, Russia, July, 2000. , pp. 168-175.
[BibTeX] |
BibTeX:
@inproceedings{Kaminskii00,
author = {Kaminskii, A. A. and Bagayev, S. N. and Ueda, K.-I. and Eichler, H. J. and Garcia-Sole, J. and Jaque, D. and Romero, J. J. and Fernandez, J. and Balda, R. and Butashin, A. V. and Agulló-Rueda, F.},
editor = {S. N. Bagayev and V. I. Denisov},
title = {New Laser and (3)-Nonlinear Properties of PbMoO_4:Nd^3+: CW Stimulated Emission at 1.0594 and 1.335 μM, High-Order Picosecond Raman Generation, and Nanosecond Self-SRS Lasing},
booktitle = {Proceedings of the Third International Symposium on Modern Problems of Laser Physics (MPLP-2000)},
year = {2000},
pages = {168--175}
}
|
| Manotas S, Agulló-Rueda F, Moreno JD, Mart\in-Palma RJ, Guerrero-Lemus R and Mart\inez-Duart JM (2000), "Depth-Resolved Microspectroscopy of Porous Silicon Multilayers", In Optical Microstructural Characterization of Semiconductors - 1999. Pittsburgh Vol. 588, pp. 155-160. Materials Research Society. |
| Abstract: We have measured micro-photoluminescence (PL) and micro-Raman spectra on the cross section of porous silicon multilayers to sample different layer depths. We find noticeable differences in the spectra of layers with different porosity, as expected from the quantum confinement of electrons and phonons in silicon nanocrystals with different average sizes. The PL emission band gets stronger, blue shifts, and narrows at the high porosity layers. The average size can be estimated from the shift. The Raman phonon band at 520 cm^-1 weakens and broadens asymmetrically towards the low energy side. The line shape can be related quantitatively with the average size by the phonon confinement model. To get a good agreement with the model we add a band at around 480 cm^-1, which has been attributed to amorphous silicon. We also have to leave as free parameters the bulk silicon phonon frequency and its line width, which depend on temperature and stress. We reduced laser power to eliminate heating effects. Then we use the change of frequency with depth to monitor the stress. At the interface with the substrate we find a compressive stress in excess of 10 kbar, which agrees with the reported lattice mismatch. Finally, average sizes are larger than those estimated from PL. |
BibTeX:
@inproceedings{Manotas00,
author = {Manotas, S. and Agulló-Rueda, F. and Moreno, J. D. and Mart\in-Palma, R. J. and Guerrero-Lemus, R. and Mart\inez-Duart, J. M.},
editor = {Ünlü, M. S. and Piqueras, J. and Kalkhoran, N. M. and Sekiguchi, T.},
title = {Depth-Resolved Microspectroscopy of Porous Silicon Multilayers},
booktitle = {Optical Microstructural Characterization of Semiconductors - 1999},
publisher = {Materials Research Society},
year = {2000},
volume = {588},
pages = {155--160},
url = {https://doi.org/10.1557/PROC-588-155},
doi = {10.1557/PROC-588-155}
}
|
| Manotas S, Agulló-Rueda F, Moreno JD, Ben-Hander F, Guerrero-Lemus R and Mart\inez-Duart JM (2000), "Laser Heating in Porous Silicon Studied by Micro-Raman Spectroscopy", Phys. Stat. Sol. (a). Vol. 182(1), pp. 331-334. |
| Abstract: We have measured the temperature rise in nanoporous silicon under strong illumination. A green laser beam was focused with a microscope objective on porous silicon films with porosities between 55% and 80%. The Raman spectrum was measured for power densities between 0.8 and 65 KW/cm^2. We obtained the temperature of the illuminated area from the shift of the phonon frecuency when phonon confinement effects are removed. The temperature depends linearly on power density. For a given power density, the temperature increases with porosity for porosities below 60% as the thermal conductivity decreases. Beyond that point, the temperature decreases because the reduction of light absorption dominates. The maximum temperature reached was 400 ^circ C for a 60% porosity sample and for a power density of 65 KW/cm^2. |
BibTeX:
@article{Manotas00b,
author = {Manotas, S. and Agulló-Rueda, F. and Moreno, J. D. and Ben-Hander, F. and Guerrero-Lemus, R. and Mart\inez-Duart, J. M.},
title = {Laser Heating in Porous Silicon Studied by Micro-Raman Spectroscopy},
journal = {Phys. Stat. Sol. (a)},
year = {2000},
volume = {182},
number = {1},
pages = {331--334},
url = {http://dx.doi.org/10.1002/1521-396X(200011)182:1<331::AID-PSSA331>3.0.CO;2-B},
doi = {10.1002/1521-396X(200011)182:1<331::AID-PSSA331>3.0.CO;2-B}
}
|
| Manotas S, Agulló-Rueda F, Moreno JD, Ben-Hander F, Guerrero-Lemus R and Mart\inez-Duart JM (2000), "Determination of Stress in Porous Silicon by Micro-Raman Spectroscopy", Phys. Stat. Sol. (a). Vol. 182(1), pp. 245-248. |
| Abstract: We have studied the stress in porous silicon films as a function of depth and porosity using micro-Raman spectroscopy. Raman spectra were measured at different points along a cross section cleaved normal to the layer planes. Each spectrum was fitted using the phonon confinement model with the bulk phonon wavenumber as a free parameter. From the variation of this parameter we get the stress using the known dependence of phonon frequency on stress for bulk silicon. We observe a compressive stress at the interface with the substrate due to the lattice mismatch between porous and bulk silicon. The maximum value of the stress increases with porosity. The results obtained by Raman micro-spectroscopy agree well with the lattice mismatch measured by X-ray diffraction reported in the literature. |
BibTeX:
@article{Manotas00c,
author = {Manotas, S. and Agulló-Rueda, F. and Moreno, J. D. and Ben-Hander, F. and Guerrero-Lemus, R. and Mart\inez-Duart, J. M.},
title = {Determination of Stress in Porous Silicon by Micro-Raman Spectroscopy},
journal = {Phys. Stat. Sol. (a)},
year = {2000},
volume = {182},
number = {1},
pages = {245--248},
url = {http://dx.doi.org/10.1002/1521-396X(200011)182:1<245::AID-PSSA245>3.0.CO;2-W},
doi = {10.1002/1521-396X(200011)182:1<245::AID-PSSA245>3.0.CO;2-W}
}
|
| Aguilar M, Carrascosa M, Agulló-López F, Agulló-Rueda F, Melloch MR and Nolte DD (1999), "Linear Electroabsorption in Semi-Insulating GaAs/AlGaAs Asymmetric Double Quantum Wells", J. Appl. Phys.. Vol. 86(7), pp. 3822-3825. |
| Abstract: Electroabsorption has been investigated in semi-insulating asymmetric GaAs/AlGaAs double quantum wells presenting high linear Stark responses, adequate for photorefractive applications. We have used the envelope function approximation to calculate the linear Stark shifts of the energy levels and select a suitable structure for the experimental study. The experimental data indicate that the response to the applied field critically depends on a complicated interplay of effects that compete or cooperate to suppress or enhance the electroabsorption. For positive field polarity, the competing contributions of the overlapping e1--hh1 and e1--hh2 transitions partially cancel the electroabsorption despite large linear Stark shifts. On the other hand, small negative fields induce large electroabsorption because the Stark shifts of the two transitions have opposite signs. |
BibTeX:
@article{Aguilar99,
author = {Aguilar, M. and M. Carrascosa and F. Agulló-López and F. Agulló-Rueda and M. R. Melloch and D. D. Nolte},
title = {Linear Electroabsorption in Semi-Insulating GaAs/AlGaAs Asymmetric Double Quantum Wells},
journal = {J. Appl. Phys.},
year = {1999},
volume = {86},
number = {7},
pages = {3822--3825},
url = {http://dx.doi.org/10.1063/1.371293},
doi = {10.1063/1.371293"}
}
|
| Callejo D, Serrano MD, Bermudez V, Dieguez E, Agulló-Rueda F and Manotas S (1999), "Incorporation of vanadium in liquid phase epitaxy films of LiNbO_3", Proc. SPIE., In Proc. SPIE 3793, Operational Characteristics and Crystal Growth of Nonlinear Optical Materials, 222 (June 28, 1999). Denver, CO, USA Vol. 3793, pp. 222-230. |
| Abstract: Second harmonic generation in Lithium Niobate (LN) thin films has been widely studied. This interest is extended to waveguides obtained by the Liquid Phase Epitaxy (LPE) technique due to the high perfection and crystallinity of the films. However the incorporation of vanadium into the film due to the growth technique is still a problem because of the absorption band of this ion in the visible zone of the spectra. In this work the LN films are obtained by the LPE technique on pure LN singledomain substrates in the horizontal LPE geometry. Several temperatures have been used in order to obtain the best crystalline quality. The starting flux used was LiVO3 80 mol%, with a Li rich melt of LiNbO3. |
BibTeX:
@inproceedings{Callejo1999SPIE,
author = {Callejo, David and Serrano, M. D. and Bermudez, Veronica and Dieguez, Ernesto and Agulló-Rueda, Fernando and Manotas, Sonsoles},
editor = {Lal, Ravindra B. and Frazier, Donald O.},
title = {Incorporation of vanadium in liquid phase epitaxy films of LiNbO_3},
booktitle = {Proc. SPIE 3793, Operational Characteristics and Crystal Growth of Nonlinear Optical Materials, 222 (June 28, 1999)},
journal = {Proc. SPIE},
year = {1999},
volume = {3793},
pages = {222--230},
url = {http://dx.doi.org/10.1117/12.351420},
doi = {10.1117/12.351420}
}
|
| Kaminski\i AA, Bagaev SN, Garc\ia-Solé J, Eichler HJ, Fernández J, Jaque D, Findeisen J, Balda R and Agulló-Rueda F (1999), "First Observations of Stimulated Emission and of Stimulated Raman Scattering in Accentric Cubic Nd^3+:Bi_12SiO_20 Crystals", Quantum Electronics. Vol. 29(1), pp. 6-8. |
| Abstract: Laser action (in the ^4F_3/2--^4I_11/2 channel) and stimulated Raman scattering were excited for the first time in an Nd3+:Bi12SiO20 single crystal at room temperature. All the observed stimulated emission and multiple Stokes and anti-Stokes lines were identified. |
BibTeX:
@article{Kaminskii99,
author = {Kaminski\i, A. A. and Bagaev, S. N. and Garc\ia-Solé, J. and Eichler, H. J. and Fernández, J. and Jaque, D. and Findeisen, J. and Balda, R. and Agulló-Rueda, F.},
title = {First Observations of Stimulated Emission and of Stimulated Raman Scattering in Accentric Cubic Nd^3+:Bi_12SiO_20 Crystals},
journal = {Quantum Electronics},
year = {1999},
volume = {29},
number = {1},
pages = {6--8},
url = {http://dx.doi.org/10.1070/qe1999v029n01ABEH001401},
doi = {10.1070/qe1999v029n01ABEH001401}
}
|
| Manotas S, Agulló-Rueda F, Moreno JD, Martín-Palma RJ, Guerrero-Lemus R and Martínez-Duart JM (1999), "Depth-Resolved Microspectroscopy of Porous Silicon Multilayers", MRS Online Proc. Libr.., December, 1999. Vol. 588(1), pp. 155-160. Springer International Publishing. |
| Abstract: We have measured micro-photoluminescence (PL) and micro-Raman spectra on the cross section of porous silicon multilayers to sample different layer depths. We find noticeable differences in the spectra of layers with different porosity, as expected from the quantum confinement of electrons and phonons in silicon nanocrystals with different average sizes. The PL emission band gets stronger, blue shifts, and narrows at the high porosity layers. The average size can be estimated from the shift. The Raman phonon band at 520 cm-1 weakens and broadens asymmetrically towards the low energy side. The line shape can be related quantitatively with the average size by the phonon confinement model. To get a good agreement with the model we add a band at around 480 cm-1, which has been attributed to amorphous silicon. We also have to leave as free parameters the bulk silicon phonon frequency and its line width, which depend on temperature and stress. We reduced laser power to eliminate heating effects. Then we use the change of frequency with depth to monitor the stress. At the interface with the substrate we find a compressive stress in excess of 10 kbar, which agrees with the reported lattice mismatch. Finally, average sizes are larger than those estimated from PL. |
BibTeX:
@article{Manotas199912155MRSOPL,
author = {Manotas, S. and Agulló-Rueda, F. and Moreno, J. D. and Martín-Palma, R. J. and Guerrero-Lemus, R. and Martínez-Duart, J. M.},
title = {Depth-Resolved Microspectroscopy of Porous Silicon Multilayers},
journal = {MRS Online Proc. Libr.},
publisher = {Springer International Publishing},
year = {1999},
volume = {588},
number = {1},
pages = {155--160},
url = {https://doi.org/10.1557/PROC-588-155},
doi = {10.1557/PROC-588-155}
}
|
| Manotas S, Agulló-Rueda F, Moreno JD, Mart\in-Palma RJ, Guerrero-Lemus R and Mart\inez-Duart JM (1999), "Depth-Resolved Microspectroscopy of Porous Silicon Multilayers", Appl. Phys. Lett.. Vol. 75(7), pp. 977-979. |
| Abstract: We have measured depth-resolved microphotoluminescence (PL) and micro-Raman spectra on the cross section of porous silicon multilayers to sample different layer depths. The PL emission band gets stronger, blueshifts, and narrows at the high porosity layers. On the contrary, the Raman band weakens and broadens. This band is fitted to the phonon confinement model. With the bulk silicon phonon frequency and its linewidth as free parameters, we obtain crystallite size, temperature, and stress as a function of depth. Sizes are larger than those estimated from PL. Laser power was reduced to eliminate heating effects. Compressive stresses in excess of 10 kbar are found in the deepest layer due to the lattice mismatch with the substrate. |
BibTeX:
@article{Manotas99,
author = {Manotas, S. and F. Agulló-Rueda and J. D. Moreno and R. J. Mart\in-Palma and R. Guerrero-Lemus and J. M. Mart\inez-Duart},
title = {Depth-Resolved Microspectroscopy of Porous Silicon Multilayers},
journal = {Appl. Phys. Lett.},
year = {1999},
volume = {75},
number = {7},
pages = {977--979},
url = {http://dx.doi.org/10.1063/1.124572},
doi = {10.1063/1.124572}
}
|
| Manotas S, Agulló-Rueda F and Mompeán F (1999), "Medidas previas para el Proyecto COCER". Thesis at: Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cient\ificas (CSIC).
[BibTeX] |
BibTeX:
@techreport{Manotas99b,
author = {Sonsoles Manotas and Fernando Agulló-Rueda and Federico Mompeán},
title = {Medidas previas para el Proyecto COCER},
school = {Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cient\ificas (CSIC)},
year = {1999}
}
|
| Moreno JD, Marcos ML, Agulló-Rueda F, Guerrero-Lemus R, Mart\in-Palma RJ, Mart\inez-Duart JM and González-Velasco J (1999), "A Galvanostatic Study of the Electrodeposition of Polypyrrole Into Porous Silicon", Thin Solid Films. Vol. 348(1-2), pp. 152-156. |
| Abstract: Polypyrrole has been electrodeposited in the interior of the pores that form the porous silicon structure, and a very significant increase of the electrical conductivity of the samples has been observed. Micro-Raman spectroscopy experiments have allowed us to measure the amount of polymer as a function of the distance from the outer porous silicon surface. The degree of filling by the polymer has been found to be highly dependent on the electropolymerization conditions, particularly the current density applied. |
BibTeX:
@article{Moreno99b,
author = {Moreno, J. D. and M. L. Marcos and F. Agulló-Rueda and R. Guerrero-Lemus and R. J. Mart\in-Palma and J. M. Mart\inez-Duart and J. González-Velasco},
title = {A Galvanostatic Study of the Electrodeposition of Polypyrrole Into Porous Silicon},
journal = {Thin Solid Films},
year = {1999},
volume = {348},
number = {1--2},
pages = {152--156},
url = {http://dx.doi.org/10.1016/S0040-6090(99)00056-5},
doi = {10.1016/S0040-6090(99)00056-5}
}
|
| Agulló-Rueda F, Moreno JD, Montoya E, Guerrero-Lemus R and Mart\inez-Duart JM (1998), "Influence of Wavelength on the Raman Line Shape in Porous Silicon", J. Appl. Phys.. Vol. 84(4), pp. 2349-2351. |
| Abstract: The line shape of the one phonon Raman peak has been used extensively in the literature to estimate the crystallite size in porous silicon. However it has been shown that the line shape obtained on top surface experiments depends on the excitation wavelength. Because the porosity depends on depth, previous results are masked by the change in penetration depth. In this communication we report depth-resolved micro-Raman spectra at 514.5 and 632.8 nm. The spectra were measured at different points along a cross section of porous silicon films. We show that even when the same layer and, therefore, the same porosity is probed the Raman peak is broader at shorter wavelengths. To explain the results we suggest a contribution of indirect gaps to the resonant Raman cross section induced by quantum confinement. |
BibTeX:
@article{Agullo-Rueda98,
author = {F. Agulló-Rueda and J. D. Moreno and E. Montoya and R. Guerrero-Lemus and J. M. Mart\inez-Duart},
title = {Influence of Wavelength on the Raman Line Shape in Porous Silicon},
journal = {J. Appl. Phys.},
year = {1998},
volume = {84},
number = {4},
pages = {2349--2351},
url = {http://dx.doi.org/10.1063/1.368303},
doi = {10.1063/1.368303}
}
|
| Mendiola J, Calzada ML, Ramos P, Mart\in MJ and Agulló-Rueda F (1998), "On the Effects of Stresses in Ferroelectric (Pb, Ca)TiO_3 Thin Films", Thin Solid Films. Vol. 315(1-2), pp. 195-201. |
| Abstract: Grazing angle X-ray diffraction, profilemetry, permittivity vs. temperature and Raman spectrometry measurements have been carried out on Ca-substituted lead titanate thin films prepared by sol-gel and deposited on Pt/TiO_2/SiO_2/(100)Si substrates. Films with thicknesses of 150 and 350 nm were obtained. The crystalline (Pb,Ca)TiO_3 films were randomly oriented with a and c parameters slightly different from those of bulk ceramics. Profilemetry measurements indicated that the films were under tensile stresses, developed during the drying of the deposited wet layer and during the thermal treatment of crystallization of the amorphous film. These stresses were confirmed by the shift obtained in the Raman frequencies of these films. As a consequence of these stresses, a positive shift of the maximum of the permittivity vs. temperature is measured. |
BibTeX:
@article{Mendiola98,
author = {Mendiola, J. and M. L. Calzada and P. Ramos and M. J. Mart\in and F. Agulló-Rueda},
title = {On the Effects of Stresses in Ferroelectric (Pb, Ca)TiO_3 Thin Films},
journal = {Thin Solid Films},
year = {1998},
volume = {315},
number = {1--2},
pages = {195-201},
url = {http://dx.doi.org/10.1016/S0040-6090(97)00698-6},
doi = {10.1016/S0040-6090(97)00698-6}
}
|
| Agulló-Rueda F, Moreno JD, Montoya E, Guerrero-Lemus R, Mart\in-Palma RJ and Mart\inez-Duart JM (1997), "Selection rules in the Raman spectrum of porous silicon", In Advances in Microcrystalline and Nanocrystalline Semiconductors - 1996. Pittsburgh Vol. 452, pp. 571-575. Materials Research Society. |
| Abstract: We have measured the Raman spectrum of porous silicon layers for different light polarizations. For the polarizations where the first-order Raman peak is forbidden in bulk silicon, porous silicon shows a band. This band is almost as intense as the one in the allowed polarizations but its lineshape is very different. The forbidden band is usually wider and shifted to lower energies with respect to the allowed band. Both bands are analyzed in terms of sample characteristics, layer depth, and excitation wavelength. |
BibTeX:
@incollection{Agullo-Rueda97,
author = {Agulló-Rueda, F. and Moreno, J. D. and Montoya, E. and Guerrero-Lemus, R. and Mart\in-Palma, R. J. and Mart\inez-Duart, J. M.},
editor = {Collins, R. W. and Fauchet, P. M. and Shimizu, I. and Vial, J. C. and Shimada, T. and Alivisatos, A. P.},
title = {Selection rules in the Raman spectrum of porous silicon},
booktitle = {Advances in Microcrystalline and Nanocrystalline Semiconductors - 1996},
publisher = {Materials Research Society},
year = {1997},
volume = {452},
pages = {571--575},
url = {https://doi.org/10.1557/PROC-452-571},
doi = {10.1557/PROC-452-571}
}
|
| de Andrés A, Agulló-Rueda F, Taboada S, Cascales C, Campá J, Ruiz-Valero C and Rasines I (1997), "Raman Active Phonons of RFe_3(BO_3)_4 R=La or Nd Single Crystals", J. Alloys and Compounds. Vol. 250(1-2), pp. 396-399. |
| Abstract: Oriented single crystals of RFe_3(BO_3)_4, with R=La or Nd, have been studied by Raman spectroscopy. Spectra with the relevant polarization configurations have been recorded in order to obtain the symmetry of the observed phonons. The factor group analysis and the correlation with the free (BO_3)^3- ion are done in order to identify most of the phonons associated with the two different types of (BO_3)^3- ion present in the crystal. The number and symmetries of the optical Raman active modes are 7 A_1 + 19 E, among which 4 A_1 + 8 E can be assigned as mostly due to (BO_3)^3- vibrations. 7 A_1 + 18 E modes were observed. The highest energy peaks have been assigned to the regular planar (BO_3)^3- and to the three irregular (BO_3)^3- groups. The two lowest energy peaks of A_1 symmetry (around 180 and 300 cm^-1) are very probably related to the BO_3 rotatory mode and to Fe displacements. R ions do not participate in A_1 symmetry modes. The E mode around 90 cm^-1 (the lowest frequency mode) is probably due to the R ions which have the longest bonds and are the heaviest ions. |
BibTeX:
@article{Andres97,
author = {de Andrés, A. and F. Agulló-Rueda and S. Taboada and C. Cascales and J. Campá and C. Ruiz-Valero and I. Rasines},
title = {Raman Active Phonons of RFe_3(BO_3)_4 R=La or Nd Single Crystals},
journal = {J. Alloys and Compounds},
year = {1997},
volume = {250},
number = {1--2},
pages = {396--399},
url = {http://dx.doi.org/10.1016/S0925-8388(96)02556-X},
doi = {10.1016/S0925-8388(96)02556-X}
}
|
| Garc\ia I, Sánchez Ol\ias J, Agulló-Rueda F and Vázquez AJ (1997), "Dielectric characterization of oxyacetylene flame-deposited diamond thin films", Diamond Relat. Mater.. Vol. 6(9), pp. 1210-1218. |
| Abstract: The dielectric properties of CVD diamond films grown by the oxyacetylene flame method for frequency dependent electrical fields have been studied. The dependence of these properties on temperature (from room temperature to 150^circC) has also been analysed. The DC conductivity due to free carriers (0) is obtained for each temperature using the Kramers-Kronig transformations of the experimental data. The values of the conductivity are very low in all cases and close to those of natural diamond (10^-16 (Ω cm)^-1); this is an indication of the low graphite content of the samples. We have also calculated the dielectric losses in the whole frequency range (100 mHz--1 MHz). A study of the relationship between the different deposition conditions with respect to the dielectric properties has been carried out. The microstructure of the films has been characterised with SEM and Raman spectroscopy. |
BibTeX:
@article{Garcia97,
author = {Garc\ia, I. and Sánchez Ol\ias, J. and F. Agulló-Rueda and A. J. Vázquez},
title = {Dielectric characterization of oxyacetylene flame-deposited diamond thin films},
journal = {Diamond Relat. Mater.},
year = {1997},
volume = {6},
number = {9},
pages = {1210--1218},
url = {http://dx.doi.org/10.1016/S0925-9635(97)00038-1},
doi = {10.1016/S0925-9635(97)00038-1}
}
|
| Linder N, Behn U, Agulló-Rueda F, Grahn HT, Schrottke L and Ploog KH (1997), "Excitonic effects in the miniband formation of graded-gap superlattices", Phys. Rev. B. Vol. 55(23), pp. 15720-15726. |
| Abstract: The formation of an electron miniband has been investigated in two differently realized graded-gap superlattices (SL's). The first SL is compositionally graded, while the second system consists of layers with different well and barrier thicknesses. The formation of the miniband in the conduction band is studied experimentally by photocurrent (PC), electroreflectance (ER), and photoluminescence (PL) spectroscopy. The experimental results are compared with the field dependence of calculated differential absorption spectra for both systems. In the compositionally graded SL, the formation of a miniband in the conduction band at finite electric fields can be clearly observed in the ER spectra. However, in the well width graded system, both the PC and the ER spectra are dominated by excitonic effects, which prevent the direct observation of the miniband formation. |
BibTeX:
@article{Linder97,
author = {Linder, N. and U. Behn and F. Agulló-Rueda and H. T. Grahn and L. Schrottke and K. H. Ploog},
title = {Excitonic effects in the miniband formation of graded-gap superlattices},
journal = {Phys. Rev. B},
year = {1997},
volume = {55},
number = {23},
pages = {15720--15726},
url = {http://dx.doi.org/10.1103/PhysRevB.55.15720},
doi = {10.1103/PhysRevB.55.15720}
}
|
| Moreno JD, Agulló-Rueda F, Montoya E, Marcos ML, González-Velasco J, Guerrero-Lemus R and Mart\inez-Duart JM (1997), "Depth-resolved micro-Raman study of porous silicon at different oxidation states", Appl. Phys. Lett.. Vol. 71(15), pp. 2166-2168. |
| Abstract: Photoluminescence (PL) and Raman spectra were measured along a cross section of porous silicon films at different oxidation times after application of anodic current transients. The average crystallite size was determined from the Raman spectra with the standard phonon confinement model. Before oxidation, the PL emission energy and crystallite size were found to be independent of the layer depth. Also, the integrated PL emission was larger for the middle layers. The effect of oxidation was a blueshift of the PL band and a decrease in the integrated emission for the outer layers. The crystallite size increases for all layers, particularly the outer ones. |
BibTeX:
@article{Moreno97,
author = {Moreno, J. D. and Agulló-Rueda, F. and Montoya, E. and Marcos, M. L. and González-Velasco, J. and Guerrero-Lemus, R. and Mart\inez-Duart, J. M.},
title = {Depth-resolved micro-Raman study of porous silicon at different oxidation states},
journal = {Appl. Phys. Lett.},
year = {1997},
volume = {71},
number = {15},
pages = {2166--2168},
url = {http://dx.doi.org/10.1063/1.119370},
doi = {10.1063/1.119370}
}
|
| Moreno JD, Agulló-Rueda F, Guerrero-Lemus R, Mart\in-Palma RJ, Mart\inez-Duart JM, Marcos ML and González-Velasco J (1997), "Deposition of polypyrrole into porous silicon", In Advances in Microcrystalline and Nanocrystalline Semiconductors - 1996. Pittsburgh Vol. 452, pp. 479-484. Materials Research Society. |
| Abstract: Polypyrrole has been electrocleposited in the interior of the pores that form the Porous Silicon structure, and a very significant increase of the electrical conductivity of the samples has been observed. The degree of filling by the polymer has been found to be highly dependent on the electropolymerization conditions. Micro-Raman Spectroscopy experiments have allowed us to measure the amount of polymer as a function to the distance from the outer PS surface. |
BibTeX:
@incollection{Moreno97b,
author = {Moreno, J. D. and Agulló-Rueda, F. and Guerrero-Lemus, R. and Mart\in-Palma, R. J. and Mart\inez-Duart, J. M. and Marcos, M. L. and González-Velasco, J.},
editor = {Collins, R. W. and Fauchet, P. M. and Shimizu, I. and Vial, J. C. and Shimada, T. and Alivisatos, A. P.},
title = {Deposition of polypyrrole into porous silicon},
booktitle = {Advances in Microcrystalline and Nanocrystalline Semiconductors - 1996},
publisher = {Materials Research Society},
year = {1997},
volume = {452},
pages = {479--484},
url = {https://doi.org/10.1557/PROC-452-479},
doi = {10.1557/PROC-452-479}
}
|
| Rams J, Agulló-Rueda F and Cabrera JM (1997), "Structure of High Index Proton Exchange LiNbO_3 Waveguides with Undegraded Nonlinear Optical Coefficients", Appl. Phys. Lett.. Vol. 71(23), pp. 3356-3358. |
| Abstract: A structural study is presented on proton exchanged LiNbO_3 waveguides prepared in benzoic acid vapor which, for z-cut substrates, were previously reported to simultaneously exhibit high index jump, very low losses, and undegraded nonlinear optical coefficients. X-ray rocking curves of z-cut guides show a unique, intense peak with the same bandwidth as the substrate peak, located at the 2-phase position of H_xLi_1-xNbO_3, as well as a small α-phase contribution. For x-cut guides only the 1-phase peak is obtained, with a bandwidth about 60% greater than the substrate peak. Distinctive features of 2 and 1 guides are also shown in micro-Raman spectra. |
BibTeX:
@article{Rams97,
author = {Rams, J. and F. Agulló-Rueda and J. M. Cabrera},
title = {Structure of High Index Proton Exchange LiNbO_3 Waveguides with Undegraded Nonlinear Optical Coefficients},
journal = {Appl. Phys. Lett.},
year = {1997},
volume = {71},
number = {23},
pages = {3356--3358},
url = {http://dx.doi.org/10.1063/1.120336},
doi = {10.1063/1.120336}
}
|
| Agulló-Rueda F, Grahn HT and Ploog K (1996), "Wannier-Stark Localization in Asymmetric Double-Well Superlattices", J. Appl. Phys. (Communications). Vol. 79(10), pp. 8106-8108. |
| Abstract: The Wannier–Stark localization of miniband states has been investigated in an asymmetric double‐well superlattice. The period consists of 3.4 and 2.0 nm GaAs quantum wells separated by 1.4 nm Al_0.15Ga_0.85As barriers. Photocurrent spectra at 6 K reveal that the lowest excitonic peak near flat band splits up into eight peaks at moderate electric fields. At very high fields only one peak remains. The observed transitions are attributed to the Stark ladder splitting of the wide‐well miniband only. This type of superlattice introduces a new degree of freedom for the tailoring of electro‐optic devices. |
BibTeX:
@article{Agullo-Rueda96,
author = {Agulló-Rueda, F. and H. T. Grahn and K. Ploog},
title = {Wannier-Stark Localization in Asymmetric Double-Well Superlattices},
journal = {J. Appl. Phys. (Communications)},
year = {1996},
volume = {79},
number = {10},
pages = {8106--8108},
url = {http://dx.doi.org/10.1063/1.362367},
doi = {10.1063/1.362367}
}
|
| Agulló-Rueda F (1996), "Semiconductores con Luz Propia", In La Luz: El Ayer, el Hoy y el Mañana. Madrid Alianza Universidad. |
BibTeX:
@incollection{Agullo-Rueda96b,
author = {F. Agulló-Rueda},
editor = {Garc\ia Solé, J. and Jaque Rechea, F.},
title = {Semiconductores con Luz Propia},
booktitle = {La Luz: El Ayer, el Hoy y el Mañana},
publisher = {Alianza Universidad},
year = {1996},
url = {http://www.alianzaeditorial.es/}
}
|
| Sochinskii NV, Diéguez E, Alves E, da Silva MF, Soares JC, Bernardi S, Garrido J and Agulló-Rueda F (1996), "Laser-Assisted Recrystallization to Improve the Surface Morphology of CdTe Epitaxial Layers", Semicond. Sci. Technol.. Vol. 11(2), pp. 248-251. |
| Abstract: Laser-assisted recrystallization has been studied in order to improve the surface morphology of CdTe layers grown on sapphire substrates by metalorganic vapour phase epitaxy (MOVPE). The recrystallization was carried out by scanning the surface of as-grown CdTe MOVPE layers with an Ar ion laser beam (λ = 514.5 nm) as the laser power varied in the 140--600 mW range. The irradiation time was in the range from 10 s to 5 min. The effect of the recrystallization layers' surface procedure on the structure has been investigated by scanning electron microscopy, Rutherford backscattering spectrometry and spectroscopic ellipsometry. Depending on the laser power and irradiation time, the recrystallization was shown to occur either within the entire layer thickness or on the layer surface. Due to recrystallization, the surface microrelief of the layers has been improved all over the recrystallized area and the surface roughness has been uniformly decreased from 1.5 μm to 0.2 μm. The data obtained show that it might be possible to engineer CdTe MOVPE layers using post-growth laser-assisted recrystallization, making them more suitable for infrared applications. |
BibTeX:
@article{Sochinskii96,
author = {Sochinskii, N. V. and E. Diéguez and E. Alves and M. F. da Silva and J. C. Soares and S. Bernardi and J. Garrido and F. Agulló-Rueda},
title = {Laser-Assisted Recrystallization to Improve the Surface Morphology of CdTe Epitaxial Layers},
journal = {Semicond. Sci. Technol.},
year = {1996},
volume = {11},
number = {2},
pages = {248--251},
url = {http://dx.doi.org/10.1088/0268-1242/11/2/018},
doi = {10.1088/0268-1242/11/2/018}
}
|
| Agulló-Rueda F and Feldmann J (1995), "Wannier-Stark localization and Bloch oscillations", In Semiconductor superlattices. Growth and electronic properties. Singapore , pp. 99-153. World Scientific. |
| Abstract: This chapter discusses the effects of an electric field on the electronic and optical properties of semiconductor superlattices. Here an ideal superlattice is considered to be an infinite periodic series of strongly coupled quantum wells. The electric field is applied in the direction perpendicular to the layer planes. From a stationary point of view the field reduces the interwell coupling and localizes the electronic states into a finite number of periods. At large fields this leads to the splitting of superlattice minibands into Wannier-Stark ladders. From a dynamic point of view electrons in the localized states describe very fast oscillations, called Bloch oscillations. These effects directly influence the static and dynamic optical properties of semiconductor superlattices producing interesting electro-optic effects. |
BibTeX:
@incollection{Agullo-Rueda95a,
author = {Agulló-Rueda, Fernando and Feldmann, Jochen},
editor = {Grahn, H. T.},
title = {Wannier-Stark localization and Bloch oscillations},
booktitle = {Semiconductor superlattices. Growth and electronic properties},
publisher = {World Scientific},
year = {1995},
pages = {99--153},
url = {https://doi.org/10.1142/9789812831439_0003},
doi = {10.1142/9789812831439_0003}
}
|
| Sochinskii NV, Diéguez E, Pal U, Piqueras J, Fernández P and Agulló-Rueda F (1995), "Elimination of Te Precipitates from CdTe Wafers", Semicond. Sci. Technol.. Vol. 10(6), pp. 870-875. |
| Abstract: Undoped and doped CdTe wafers have been thermally annealed in Ga melt, or in Cd vapour or in a vacuum to eliminate Te precipitates from the volume of the wafers. The effect of annealing conditions on the transformation of Te precipitates has been studied by Raman scattering (RS) and cathodoluminescence (CL) techniques. The RS and CL spectra of the as-grown and annealed wafers are discussed in connection with the doping and native structural defects and residual impurities. The kinetics of elimination of Te precipitates was found to be similar in the undoped and doped wafers. The rate of elimination is the highest for the annealing in Ga melt. Precipitate-free wafers have been obtained by annealing in Ga melt at 600 degrees C for 24 h. Simultaneously with the elimination of Te precipitates, Ga melt causes the in-diffusion of Ga atoms into the wafers. This implies that annealing in Ga melt could be a superior procedure for the elimination of Te precipitates from CdTe wafers in which Ga doping is not important or is desired. |
BibTeX:
@article{Sochinskii95,
author = {Sochinskii, N. V. and E. Diéguez and U. Pal and J. Piqueras and P. Fernández and F. Agulló-Rueda},
title = {Elimination of Te Precipitates from CdTe Wafers},
journal = {Semicond. Sci. Technol.},
year = {1995},
volume = {10},
number = {6},
pages = {870--875},
url = {http://dx.doi.org/10.1088/0268-1242/10/6/020},
doi = {10.1088/0268-1242/10/6/020}
}
|
| Sochinskii NV, Serrano MD, Diéguez E, Agulló-Rueda F, Pal U, Piqueras J and Fernández P (1995), "Effect of Thermal Annealing on Te Precipitates in CdTe Wafers Studied by Raman Scattering and Cathodoluminescence", J. Appl. Phys.. Vol. 77(6), pp. 2806-2808. |
| Abstract: A combination of Raman scattering and cathodoluminescence techniques has been used to study the spatial distribution of Te precipitates in the volume of CdTe wafers. Starting with the as‐grown crystals with random distribution of precipitates over the whole volume, improvement at different stages of thermal annealing is demonstrated. As‐grown p‐CdTe wafers were annealed at 500--600^circC either in Ga melt or in Cd vapor for 2 or 22 h. The kinetics of dissolution of Te precipitates was found to be similar for both the Ga melt and Cd vapor annealing processes. Short‐time annealing causes the disappearance of small Te precipitates, while the larger ones, 5--10 μm in size which decorate the extended structural defects, still remain. After a long‐time annealing, the complete disappearance of Te precipitates occurs in the wafers volume. Interestingly, it was observed that the disappearance of Te precipitates during annealing starts in the central part of the bulk wafer and is followed by a precipitate gettering at the wafer surface. This implies that it is possible to obtain precipitate‐free CdTe wafers by postgrowth annealing. |
BibTeX:
@article{Sochinskii95b,
author = {Sochinskii, N. V. and M. D. Serrano and E. Diéguez and F. Agulló-Rueda and U. Pal and J. Piqueras and P. Fernández},
title = {Effect of Thermal Annealing on Te Precipitates in CdTe Wafers Studied by Raman Scattering and Cathodoluminescence},
journal = {J. Appl. Phys.},
year = {1995},
volume = {77},
number = {6},
pages = {2806--2808},
url = {http://dx.doi.org/10.1063/1.358687},
doi = {10.1063/1.358687}
}
|
| Agulló-López F, Cabrera JM and Agulló-Rueda F (1994), "Electrooptics: Phenomena, materials and applications" New York Academic Press. |
| Abstract: This comprehensive text provides an understanding of the physical phenomenon behind electrooptics. It describes in detail modern electrooptic materials and operative physical mechanisms, and devotes a full chapter to the new materials engineering that is contributing to the development of low-dimensional systems. The book also reviews device applications in both bulk and waveguide technologies. |
BibTeX:
@book{Agullo-Lopez94a,
author = {Agulló-López, Fernando and Cabrera, José Manuel and Agulló-Rueda, Fernando},
title = {Electrooptics: Phenomena, materials and applications},
publisher = {Academic Press},
year = {1994},
url = {https://doi.org/10.1016/C2009-0-21166-4},
doi = {10.1016/C2009-0-21166-4}
}
|
| Agulló-Rueda F, Grahn HT and Ploog K (1994), "Nonthermal Occupation of Γ and X States in GaAs/AlAs Superlattices", Phys. Rev. B. Vol. 49(20), pp. 14456-14459. |
| Abstract: We have studied the photoluminescence (PL) emission from a GaAs/AlAs asymmetric-double-well superlattice with indirect band gap as a function of temperature and applied electric field. The PL spectrum consists of two peaks, with a separation of only 21 meV, originating from the recombination of wide-well heavy holes with either X electrons of the barrier or Γ electrons of the wide well, respectively. The PL intensity ratio of the two peaks shows a strong nonthermal population between Γ and X states near flatband, because in this sample the transfer from Γ to X after photoexcitation can be induced only by absorption of phonons with a large momentum. The small Γ-X separation and the long recombination time of X electrons results in the filling of the X states that are at the same energy as the Γ minimum, blocking Γ-X transfer by phonon emission or interface (roughness) scattering. |
BibTeX:
@article{Agullo-Rueda94,
author = {Agulló-Rueda, F. and Grahn, H. T. and Ploog, K.},
title = {Nonthermal Occupation of Γ and X States in GaAs/AlAs Superlattices},
journal = {Phys. Rev. B},
year = {1994},
volume = {49},
number = {20},
pages = {14456--14459},
url = {http://dx.doi.org/10.1103/PhysRevB.49.14456},
doi = {10.1103/PhysRevB.49.14456}
}
|
| Grahn HT, Agulló-Rueda F, D'Intino A, Schmidt KH, Döhler GH and Ploog K (1994), "Miniband formation in graded-gap superlattices", Solid-State Electron.. Vol. 37(4-6), pp. 835-838. |
| Abstract: A graded-gap superlattice has been investigated to study the formation of miniband states at finite electric fields. In contrast to conventional superlattices only one type of states, either the conduction band or the valence band states, form a miniband. The transition from extended miniband states at finite electric fields back to localized states is clearly observed with increasing electric field. Calculations of the miniband structure using different methods support the formation of a miniband in the conduction band at finite electric fields. |
BibTeX:
@article{Grahn94,
author = {Grahn, H. T. and F. Agulló-Rueda and A. D'Intino and K. H. Schmidt and G. H. Döhler and K. Ploog},
title = {Miniband formation in graded-gap superlattices},
journal = {Solid-State Electron.},
year = {1994},
volume = {37},
number = {4--6},
pages = {835--838},
url = {http://dx.doi.org/10.1016/0038-1101(94)90308-5},
doi = {10.1016/0038-1101(94)90308-5}
}
|
| Sánchez-Dehesa J, Agulló-Rueda F, Mart\inez-Pastor J, Vinatieri A, Meseguer F, Colocci M, Mayoral R, Porto JA, López C, Ceschin AM, Grandjean N and Massies J (1994), "Lateral localization in strained InGaAs/GaAs quantum wells", In Formation of semiconductor interfaces. Singapore , pp. 558-561. World Scientific. |
BibTeX:
@incollection{Sanchez-Dehesa94,
author = {Sánchez-Dehesa, J. and Agulló-Rueda, F. and Mart\inez-Pastor, J. and Vinatieri, A. and Meseguer, F. and Colocci, M. and Mayoral, R. and Porto, J. A. and López, C. and Ceschin, A. Marti and Grandjean, N. and Massies, J.},
editor = {Lengerer, B. and Lüth, H. and Mönch, W. and Pollmann, J.},
title = {Lateral localization in strained InGaAs/GaAs quantum wells},
booktitle = {Formation of semiconductor interfaces},
publisher = {World Scientific},
year = {1994},
pages = {558--561},
url = {https://doi.org/10.1142/2171},
doi = {10.1142/9789814535113}
}
|
| Agulló-Rueda F, D'Intino A, Schmidt KH, Döhler GH, Grahn HT and Ploog K (1993), "Miniband formation at finite electric fields in a graded-gap superlattice", Europhys. Lett.. Vol. 23(4), pp. 283-288. |
| Abstract: We have investigated a graded-gap superlattice with differential photocurrent spectroscopy at 77 K. The lowest conduction subband exhibits with increasing electric field a transition from localized to extended miniband states and back to localized states. The transition from the extended miniband states at finite electric fields back to localized states is observed. Calculations of the miniband width using different methods support the interpretation of miniband formation at finite electric fields. |
BibTeX:
@article{Agullo-Rueda93,
author = {Agulló-Rueda, F. and A. D'Intino and K. H. Schmidt and G. H. Döhler and H. T. Grahn and K. Ploog},
title = {Miniband formation at finite electric fields in a graded-gap superlattice},
journal = {Europhys. Lett.},
year = {1993},
volume = {23},
number = {4},
pages = {283--288},
url = {http://dx.doi.org/10.1209/0295-5075/23/4/008},
doi = {10.1209/0295-5075/23/4/008}
}
|
| Agulló-Rueda F (1993), "Espectroscop\ia Raman", In Introducción a la Ciencia de Materiales. Madrid Publicaciones del CSIC. |
BibTeX:
@incollection{Agullo-Rueda93ram,
author = {F. Agulló-Rueda},
editor = {Albella, J. M. and Cintas, A. M. and Miranda, T. and Serratosa, J. M.},
title = {Espectroscop\ia Raman},
booktitle = {Introducción a la Ciencia de Materiales},
publisher = {Publicaciones del CSIC},
year = {1993},
url = {http://www.csic.es/}
}
|
| Mart\inez-Pastor J, Agulló-Rueda F, Vinattieri A, Meseguer F, Sánchez-Dehesa J, Colocci M, Mayoral R, Ceschin AM, Grandjean N and Massies J (1993), "Localization in Highly Strained In_0.35Ga_0.65As/GaAs Ultrathin Quantum Wells", Superlattices & Microstructures. Vol. 14(1), pp. 39-47. |
| Abstract: We have studied different strained InGaAs/GaAs ultrathin quantum wells grown on vicinal surfaces for various terrace lengths and In contents. From photoluminescence experiments we observe an enhancement of the continuum density of states of quantum wells with large In content (x = 0.35). We associate this behavior with the localization of carriers in regions of quasi one-dimensional confinement which are induced by fluctuations in the lateral periodicity of the strained layers. This assumption is supported by time resolved measurements as well. |
BibTeX:
@article{Martinez-Pastor93,
author = {Mart\inez-Pastor, J. and F. Agulló-Rueda and A. Vinattieri and F. Meseguer and J. Sánchez-Dehesa and M. Colocci and R. Mayoral and A. Marti Ceschin and N. Grandjean and J. Massies},
title = {Localization in Highly Strained In_0.35Ga_0.65As/GaAs Ultrathin Quantum Wells},
journal = {Superlattices & Microstructures},
year = {1993},
volume = {14},
number = {1},
pages = {39--47},
url = {http://dx.doi.org/10.1006/spmi.1993.1100},
doi = {10.1006/spmi.1993.1100}
}
|
| Meseguer F, Agulló-Rueda F, López C, Sánchez-Dehesa J, Massies J and Ceschin AM (1993), "Lateral superlattice effects in very narrow strained semiconductor quantum wells grown on vicinal surfaces", Phys. Rev. B. Vol. 47(20), pp. 13880-13883. |
| Abstract: The existence of lateral-superlattice effects in narrow In_xGa_1-xAs/GaAs strained quantum wells grown on GaAs vicinal substrates is reported. The effects have been probed by photoluminescence excitation under magnetic field and compared to a theoretical model. Prior work indicates that strained epitaxial layers grown on vicinal surfaces may present a tilt angle between the substrate plane and the epilayer plane that depends on the lattice mismatch. This provokes strong lateral modulation of the potential induced by inhomogeneity of the built-in strain. Our results are consistent with strong lateral-superlattice effects. |
BibTeX:
@article{Meseguer93,
author = {Meseguer, F. and F. Agulló-Rueda and C. López and J. Sánchez-Dehesa and J. Massies and A. M. Ceschin},
title = {Lateral superlattice effects in very narrow strained semiconductor quantum wells grown on vicinal surfaces},
journal = {Phys. Rev. B},
year = {1993},
volume = {47},
number = {20},
pages = {13880--13883},
url = {http://dx.doi.org/10.1103/PhysRevB.47.13880},
doi = {10.1103/PhysRevB.47.13880}
}
|
| Sánchez-Dehesa J, Porto JA, Agulló-Rueda F and Meseguer F (1993), "Electronic energy levels of quantum well wires", J. Appl. Phys.. Vol. 73(10), pp. 5027-5031. |
| Abstract: An efficient variational method to solve the two‐dimensional Schrödinger equation using a basis set of cubic B splines is introduced. The method, which uses the effective mass theory and the envelope function approximation, is applied to find the energy levels of quantum‐well wires of different shapes. Finally, for rectangular wires a very simple method based on a special decomposition of the V(x,y) potential is used to reduce the problem to two one‐dimensional equations. This gives very good results even for very narrow wires, where the conventional decomposition V(x,y) = V(x) + V(y) fails. |
BibTeX:
@article{Sanchez-Dehesa93,
author = {Sánchez-Dehesa, J. and J. A. Porto and F. Agulló-Rueda and F. Meseguer},
title = {Electronic energy levels of quantum well wires},
journal = {J. Appl. Phys.},
year = {1993},
volume = {73},
number = {10},
pages = {5027--5031},
url = {http://dx.doi.org/10.1063/1.353772},
doi = {10.1063/1.353772}
}
|
| Agulló-Rueda F, Grahn HT, Fischer A and Ploog K (1992), "Local origin of photocurrent in semiconductor superlattices", Phys. Rev. B (Rapid Communications). Vol. 45(15), pp. 8818(R)-8821(R). |
| Abstract: To trace the origin of photocurrent (PC) in semiconductor superlatices, we have studied the PC spectra as a function of the applied electric field in a novel compositionally graded superlattice, where each well produces a separate peak. The sample consisted of 15 quasiperiods of 40/20-Å Al_xGa_1-xAs/Al_yGa_1-yAs [x = 0.03(n-1), y = x + 0.3, and (n = 1, 15)]. We show that the PC is due to the transport of electrons with no significant contribution from the holes. At low electric field, when the transport is very slow, the PC originates from a few wells close to the substrate, thus providing local information, unlike optical absorption. As the field increases the active region expands and finally covers the whole superlattice. |
BibTeX:
@article{Agullo-Rueda92,
author = {Agulló-Rueda, F. and Grahn, H. T. and Fischer, A. and Ploog, K.},
title = {Local origin of photocurrent in semiconductor superlattices},
journal = {Phys. Rev. B (Rapid Communications)},
year = {1992},
volume = {45},
number = {15},
pages = {8818(R)--8821(R)},
url = {http://dx.doi.org/10.1103/PhysRevB.45.8818},
doi = {10.1103/PhysRevB.45.8818}
}
|
| Agulló-Rueda F (1992), "El oscilador armónico: una herramienta de la F\isica actual", In Temas Actuales de la F\isica. Madrid , pp. 35-46. Ediciones de la Universidad Autónoma de Madrid. |
BibTeX:
@incollection{Agullo-Rueda92b,
author = {Agulló-Rueda, F.},
editor = {Garc\ia Solé, J. and Jaque Rechea, F.},
title = {El oscilador armónico: una herramienta de la F\isica actual},
booktitle = {Temas Actuales de la F\isica},
publisher = {Ediciones de la Universidad Autónoma de Madrid},
year = {1992},
pages = {35--46},
url = {http://www.uam.es/servicios/otros/spublicaciones/}
}
|
| Carrascosa M, Agulló-Rueda F and Agulló-López F (1992), "Steady holographic gratings in semiconductor multiple quantum wells", Appl. Phys. A. Vol. 55(1), pp. 25-29. |
| Abstract: A theoretical model based on the Dember mechanism is proposed to describe the steady state photorefractive gratings generated in semiconductor multiple quantum wells (MQW). It has been applied to an GaAs/AlGaAs MQW in parallel configuration (external electric field applied parallel to the MQW layers) for which recent experimental data are available. The model predicts a dependence of the first-order diffraction efficiency on the applied field in qualitative accordance with experiments, including the occurrence of saturation at high field values. Absolute values of the efficiencies are in good agreement with the experimental ones. Finally, high second-order diffraction efficiencies, associated with the development of a perpendicular space charge field, are also predicted by the model. |
BibTeX:
@article{Carrascosa92,
author = {Carrascosa, M. and Agulló-Rueda, F. and Agulló-López, F.},
title = {Steady holographic gratings in semiconductor multiple quantum wells},
journal = {Appl. Phys. A},
year = {1992},
volume = {55},
number = {1},
pages = {25--29},
url = {http://dx.doi.org/10.1007/BF00324597},
doi = {10.1007/BF00324597}
}
|
| Hong JM, Awschalom DD, Agulló-Rueda F and Chang LL (1991), "Growth and novel properties of magnetic heterostructures by molecular beam epitaxy", J. Cryst. Growth. Vol. 111(1-4), pp. 1016-1023. |
| Abstract: Diluted magnetic semiconductor Cd_1-xMn_xTe-Cd_1-yMn_yTe heterostructures of various layer thickness, where 0 ≤ x, y ≤ 0.4, were grown by molecular beam epitaxy for optical and magnetic studies of reduced-dimensional systems. X-ray diffraction patterns, low-temperature photoluminescence spectra (PL), and AC magnetic susceptibility measurements were used to verify the integrity of these structures. The carrier quantization in the quantum wells were revealed by the magnetic response in a magneto-optic microsusceptometer as well as by the results of PL measurement. These SLs were used to study the dimensional cross-over of the spin-glass phase. In addition, a magnetic-field-induced transition from type I to type II superlattice was observed. |
BibTeX:
@article{Hong91,
author = {Hong, J. M. and D. D. Awschalom and F. Agulló-Rueda and L. L. Chang},
title = {Growth and novel properties of magnetic heterostructures by molecular beam epitaxy},
journal = {J. Cryst. Growth},
year = {1991},
volume = {111},
number = {1--4},
pages = {1016--1023},
url = {http://dx.doi.org/10.1016/0022-0248(91)91124-S},
doi = {10.1016/0022-0248(91)91124-S}
}
|
| Agulló-Rueda F, Mendez EE, Brum JA and Hong JM (1990), "Coherence and localization in semiconductor superlattices under electric fields", Surf. Sci.. Vol. 228, pp. 80-83. |
| Abstract: Using optical techniques, we have demonstrated that the quantum coherence of electron states in GaAs/GaAlAs superlattices under electric fields increases drastically as the period, D, and the electric field, E, decrease, reaching at least ten periods at zero field when . The electric field localizes the states, breaking the superlattice minibands into Stark ladders, and producing a transition from three- to quasi-two-dimensional excitons. These effects are manifested, respectively, by the appearance of oscillations in the absorption coefficient, which are periodic both in energy and in E^-1, and by a sharp increase in the intrawell exciton binding energy. |
BibTeX:
@article{Agullo-Rueda90a,
author = {Agulló-Rueda, F. and E. E. Mendez and J. A. Brum and J. M. Hong},
title = {Coherence and localization in semiconductor superlattices under electric fields},
journal = {Surf. Sci.},
year = {1990},
volume = {228},
pages = {80--83},
note = {1--3},
url = {http://dx.doi.org/10.1016/0039-6028(90)90263-8},
doi = {10.1016/0039-6028(90)90263-8}
}
|
| Agulló-Rueda F, Brum JA, Mendez EE and Hong JM (1990), "Change in dimensionality of superlattice excitons induced by an electric field", Phys. Rev. B. Vol. 41(3), pp. 1676-1679. |
| Abstract: We have observed an electric-field-induced change in the dimensionality of excitons in superlattices, from three to quasi-two dimensions. The exciton binding energy of a (40 /(40 GaAs/(GaAl)As superlattice, determined from low-temperature photocurrent experiments, increases more than 6 meV by the action of an electric field perpendicular to the superlattice layers. This sharp increase, from nearly the bulk value of GaAs at very low fields to the isolated-quantum-well value at high fields, is a direct consequence of the Stark localization of electrons and holes in superlattices. |
BibTeX:
@article{Agullo-Rueda90b,
author = {Agulló-Rueda, F. and Brum, J. A. and Mendez, E. E. and Hong, J. M.},
title = {Change in dimensionality of superlattice excitons induced by an electric field},
journal = {Phys. Rev. B},
year = {1990},
volume = {41},
number = {3},
pages = {1676--1679},
url = {http://dx.doi.org/10.1103/PhysRevB.41.1676},
doi = {10.1103/PhysRevB.41.1676}
}
|
| Agulló-Rueda F, Mendez EE, Ohno H and Hong JM (1990), "Interactions between extended and localized states in superlattices", Phys. Rev. B. Vol. 42(2), pp. 1470-1473. |
| Abstract: We have observed electric-field-induced interactions between the extended states of a (40 -(15 GaAs-Ga0.65Al0.35As superlattice and the localized state of an 80-Å terminating GaAs well. At fields such that the energy of an extended state was close to that of the localized level, low-temperature (5-K) photocurrent spectra associated with interband transitions exhibited three pronounced doublets of peaks with characteristic resonant and anticrossing behavior. As the two levels approach each other, the initially asymmetrical peak intensities first become of comparable strengths and then exchange their roles in the resulting asymmetrical peak intensities as the states begin to repel each other. A comparison of the experimental results with numerical solutions of Schrödinger's equation showed that the doublets result from the interaction of the localized state with the three superlattice states of highest energy, centered aroung its last three wells. |
BibTeX:
@article{Agullo-Rueda90c,
author = {Agulló-Rueda, F. and Mendez, E. E. and Ohno, H. and Hong, J. M.},
title = {Interactions between extended and localized states in superlattices},
journal = {Phys. Rev. B},
year = {1990},
volume = {42},
number = {2},
pages = {1470--1473},
url = {http://dx.doi.org/10.1103/PhysRevB.42.1470},
doi = {10.1103/PhysRevB.42.1470}
}
|
| Brum JA and Agulló-Rueda F (1990), "Stark ladder excitonic transitions", Surf. Sci. Vol. 229(1-3), pp. 472-475. |
| Abstract: We have calculated the binding energy and the transition energies of excitons for a superlattice under an external electric field applied along the growth direction. At low fields the binding energy shifts strongly showing the localization of the superlattice states into the Stark ladder states. For higher fields the energy levels observe a shift associated to the single quantum well Stark effect. We also discuss the contribution of superlattice fluctuations to the carrier confinement. |
BibTeX:
@article{Brum90,
author = {Brum, J. A. and F. Agulló-Rueda},
title = {Stark ladder excitonic transitions},
journal = {Surf. Sci},
year = {1990},
volume = {229},
number = {1--3},
pages = {472--475},
url = {http://dx.doi.org/10.1016/0039-6028(90)90933-Y},
doi = {10.1016/0039-6028(90)90933-Y}
}
|
| Fukuzawa T, Mendez E. E, Agulló-Rueda F, Hong J. M, Masuhara N and Kano SS (1990), "Anomalous Photoluminesccence Line Narrowing in Coupled Double Quantum Wells [in Japanese]", J-STAGE., In Meeting Abstracts of the Physical Society of Japan., Mar, 1990. Vol. 45(3), pp. 172. The Physical Society of Japan. |
| Abstract: J-STAGE |
BibTeX:
@inproceedings{Fukuzawa1990MAPSJ3,
author = {Fukuzawa, T and Mendez E., E. and Agulló-Rueda, F. and Hong J., M. and Masuhara, N. and Kano, S. S.},
title = {Anomalous Photoluminesccence Line Narrowing in Coupled Double Quantum Wells [in Japanese]},
booktitle = {Meeting Abstracts of the Physical Society of Japan},
journal = {J-STAGE},
publisher = {The Physical Society of Japan},
year = {1990},
volume = {45},
number = {3},
pages = {172},
url = {https://doi.org/10.11316/jpsgaiyod.45.3.0_172_2},
doi = {10.11316/jpsgaiyod.45.3.0_172_2}
}
|
| Harwit A, Hsu C, Agulló-Rueda F and Chang LL (1990), "Observation of Miniband Formation in the CdTe/Cd_1-xMn_xTe Quantum Well System", Appl. Phys. Lett.. Vol. 57(17), pp. 1769-1771. |
| Abstract: We report the effects of perpendicular electric fields on the eigenenergies of the CdTe/Cd_1-xMn_xTe quantum well system. The samples are probed at 6 K using photoluminescence. In an electric field, the photoluminescence spectra of wide‐barrier quantum well samples red shifted, consistent with the quantum‐confined Stark effect. The spectra of narrow‐barrier superlattice samples blue shifted, indicative of miniband reduction to localized states. A linear blue shift was observed up to a field of 50 kV/cm after which saturation occurred. Additionally, we have observed luminescence which appeared to arise from transitions between adjacent wells. No striking effects were observed at the paramagnetic‐spin glass transition temperature. |
BibTeX:
@article{Harwit90,
author = {Harwit, A. and C. Hsu and F. Agulló-Rueda and L. L. Chang},
title = {Observation of Miniband Formation in the CdTe/Cd_1-xMn_xTe Quantum Well System},
journal = {Appl. Phys. Lett.},
year = {1990},
volume = {57},
number = {17},
pages = {1769--1771},
url = {http://dx.doi.org/10.1063/1.104062},
doi = {10.1063/1.104062}
}
|
| Mendez EE, Agulló-Rueda F and Hong JM (1990), "Temperature Dependence of the Electronic Coherence of GaAs-GaAlAs Superlattices", Appl. Phys. Lett.. Vol. 56(25), pp. 2545-2547. |
| Abstract: We have shown that the coherence length of electrons in a 55-period GaAs-GaAlAs superlattice does not depend strongly on temperature in the range 5--292 K, varying from 17 periods at 5 K to a minimum of nine periods at room temperature. The quantum coherence was determined by photocurrent spectroscopy experiments that exploit the formation of Stark ladders in superlattices under electric fields. |
BibTeX:
@article{Mendez90,
author = {Mendez, E. E. and F. Agulló-Rueda and J. M. Hong},
title = {Temperature Dependence of the Electronic Coherence of GaAs-GaAlAs Superlattices},
journal = {Appl. Phys. Lett.},
year = {1990},
volume = {56},
number = {25},
pages = {2545--2547},
url = {http://dx.doi.org/10.1063/1.102882},
doi = {10.1063/1.102882}
}
|
| Ohno H, Mendez EE, Brum JA, Hong JM, Agulló-Rueda F, Chang LL and Esaki L (1990), "Observation of 'Tamm States' in Superlattices", Phys. Rev. Lett.. Vol. 64(21), pp. 2555-2558. |
| Abstract: We have observed localized surface states (Tamm states) intentionally introduced in AlGaAs/GaAs superlattices by a terminating layer of AlAs. The formation of these states is manifested by excitonic interband transitions in photoluminescence excitation spectra. Critical confirmation is provided by photocurrent experiments under an electric field that show additional transitions as well as anticrossing interactions between the Tamm states and the Stark-ladder states associated with the superlattice. |
BibTeX:
@article{Ohno90,
author = {Ohno, H. and Mendez, E. E. and Brum, J. A. and Hong, J. M. and Agulló-Rueda, F. and Chang, L. L. and Esaki, L.},
title = {Observation of 'Tamm States' in Superlattices},
journal = {Phys. Rev. Lett.},
year = {1990},
volume = {64},
number = {21},
pages = {2555--2558},
url = {http://dx.doi.org/10.1103/PhysRevLett.64.2555},
doi = {10.1103/PhysRevLett.64.2555}
}
|
| Agulló-Rueda F, Mendez EE and Hong JM (1989), "Quantum coherence in semiconductor superlattices", Phys. Rev. B (Rapid Communications). Vol. 40(2), pp. 1357(R)-1360(R). |
| Abstract: Using photocurrent spectroscopy, we have demonstrated that the quantum coherence in GaAs-Ga_1-xAl_xAs superlattices increases with decreasing superlattice period D, and that it is maintained for at least eight periods when D = 60 AA. The coherence length was determined from the number of observed interband transitions between the valence- and conduction-band Stark ladders, formed when an electric field was applied along the superlattice direction. As an additional manifestation of the Stark ladder, the photocurrent showed strong oscillations, periodic in the reciprocal of the electric field, which gave rise to regions of pronounced negative differential resistance. |
BibTeX:
@article{Agullo-Rueda89,
author = {Agulló-Rueda, F. and Mendez, E. E. and Hong, J. M.},
title = {Quantum coherence in semiconductor superlattices},
journal = {Phys. Rev. B (Rapid Communications)},
year = {1989},
volume = {40},
number = {2},
pages = {1357(R)--1360(R)},
url = {http://dx.doi.org/10.1103/PhysRevB.40.1357},
doi = {10.1103/PhysRevB.40.1357}
}
|
| Mendez EE and Agulló-Rueda F (1989), "Optical properties of quantum wells and superlattices under electric fields", J. Lumin.. Vol. 44(4-6), pp. 223-232. |
| Abstract: We review the effects of a longitudinal electric field on the optical properties of semiconductor quantum wells and superlattices, emphasizing recent developments on the latter, such as the observation of the Stark ladder, field-induced localization, and change in dimensionality of superlattice excitons. |
BibTeX:
@article{Mendez89,
author = {Mendez, E. E. and F. Agulló-Rueda},
title = {Optical properties of quantum wells and superlattices under electric fields},
journal = {J. Lumin.},
year = {1989},
volume = {44},
number = {4--6},
pages = {223--232},
url = {http://dx.doi.org/10.1016/0022-2313(89)90059-8},
doi = {10.1016/0022-2313(89)90059-8}
}
|
| Agulló-Rueda F, Mendez EE and Hong JM (1988), "Doubly Resonant Raman Scattering Induced by an Electric Field", Phys. Rev. B. Vol. 38(17), pp. 12720-12723. |
| Abstract: By applying a variable electric field to a 30-35 Å GaAs/Ga_0.65Al_0.35As superlattice we have achieved tunable doubly resonant Raman processes, in which both the incident and the scattered light are in resonance with electronic transitions. The resonances, which involve states of the field-induced Stark ladder, manifest themselves as strong enhancements in the intensity of Raman scattering associated with the longitudinal optical phonon of GaAs. The dependence of the double resonances on field and photon energy provides direct information on the superlattice states, in very good agreement with results of photocurrent and photoluminescence experiments. |
BibTeX:
@article{Agullo-Rueda88,
author = {Agulló-Rueda, F. and Mendez, E. E. and Hong, J. M.},
title = {Doubly Resonant Raman Scattering Induced by an Electric Field},
journal = {Phys. Rev. B},
year = {1988},
volume = {38},
number = {17},
pages = {12720--12723},
url = {http://dx.doi.org/10.1103/PhysRevB.38.12720},
doi = {10.1103/PhysRevB.38.12720}
}
|
| Agulló-Rueda F, Calleja JM and Bartolomé J (1988), "Raman spectroscopy of the ammonium Ion in NH_4ZnF_3 and NH_4MnF_3 perovskites: temperature dependence", J. Phys. C: Solid State Phys.. Vol. 21(7), pp. 1287-1297. |
| Abstract: The Raman spectra corresponding to the internal vibrations of the ammonium ion in NH_4MnF_3 and NH_4ZnF_3 single crystals have been measured from 10 to 300 K. The spectra clearly show the existence of a structural phase transition from cubic to tetragonal symmetry. The splitting of the internal modes is compatible with effective symmetries of the ammonium ion of D_2d and C_s in the cubic and tetragonal phases, respectively. The temperature dependence of the symmetric stretching mode in the cubic phase is linear with a slope of 0.231 cm^-1 K^-1 for NH_4MnF_3. This has the opposite sign to that due only to the crystal expansion as obtained by applying hydrostatic pressure. A sharp band appearing only in the spectrum of NH_4MnF_3 just below the crystallographic phase transition originates in a strong symmetry-induced 2 + 4:1 Fermi resonance. |
BibTeX:
@article{Agullo-Rueda88b,
author = {Agulló-Rueda, F. and J. M. Calleja and J. Bartolomé},
title = {Raman spectroscopy of the ammonium Ion in NH_4ZnF_3 and NH_4MnF_3 perovskites: temperature dependence},
journal = {J. Phys. C: Solid State Phys.},
year = {1988},
volume = {21},
number = {7},
pages = {1287--1297},
url = {http://dx.doi.org/10.1088/0022-3719/21/7/016},
doi = {10.1088/0022-3719/21/7/016}
}
|
| Mendez EE, Agulló-Rueda F and Hong JM (1988), "Stark Localization in GaAs-GaAlAs Superlattices under an Electric Field", Phys. Rev. Lett.. Vol. 60(23), pp. 2426-2429. |
| Abstract: We have observed that a strong electric field cal E shifts to higher energies the photoluminescence and photocurrent peaks of a GaAs-Ga_0.65Al_0.35As superlattice of period D (=65 , which we explain by a field-induced localization of carriers to isolated quantum wells. Good agreement is found between observed and calculated shifts when the large field-induced increase of the exciton binding energy is taken into account. At moderate fields [≈ (2--3) × 10^4 V/cm], the coupling between adjacent wells is manifested by four additional peaks that shift at the rates ± e cal E D and ± 2 e cal E D and correspond to transitions that involve different levels of the Stark ladder. |
BibTeX:
@article{Mendez88,
author = {Mendez, E. E. and Agulló-Rueda, F. and Hong, J. M.},
title = {Stark Localization in GaAs-GaAlAs Superlattices under an Electric Field},
journal = {Phys. Rev. Lett.},
year = {1988},
volume = {60},
number = {23},
pages = {2426--2429},
url = {http://dx.doi.org/10.1103/PhysRevLett.60.2426},
doi = {10.1103/PhysRevLett.60.2426}
}
|
| Agulló-Rueda F, Calleja JM and Tornero JD (1987), "Raman Spectroscopy of NH_4MnCl_3 Crystal", Solid State Commun.. Vol. 62(8), pp. 551-554. |
| Abstract: The Raman spectra of the NH_4MnCl_3 crystal above and below the crystallographic phase transition are given for both the lattice and the ammonium modes. The results are discussed in terms of the structure of the crystal lattice and its influence on the symmetry of the ammonium ions. |
BibTeX:
@article{Agullo-Rueda87,
author = {Agulló-Rueda, F. and J. M. Calleja and J. D. Tornero},
title = {Raman Spectroscopy of NH_4MnCl_3 Crystal},
journal = {Solid State Commun.},
year = {1987},
volume = {62},
number = {8},
pages = {551--554},
url = {http://dx.doi.org/10.1016/0038-1098(87)91084-2},
doi = {10.1016/0038-1098(87)91084-2}
}
|
| Agulló-Rueda F, Calleja JM, Martini M, Spinolo G and Cariati F (1987), "Raman and Infrared Spectra of Transition Metal Halide Hexahydrates", J. Raman Spectros.. Vol. 18(7), pp. 485-491. |
| Abstract: The Raman and infrared spectra of NiCl_2 ⋅ 6H_2O, NiCl_2⋅6D_2O, CoCl_2⋅6H_2O, CoCl_2⋅6D_2O and CoBr_2⋅6H_2O single crystals have been measured in the range 3600--30 cm^-1 (Raman) and 3800--400 cm^-1 (IR). The water internal modes have been best assigned for NiCl_2⋅6H_2O, including Fermi resonance effects. The corresponding Raman intensities have been interpreted in terms of the free molecule Raman tensors. Among the lattice vibrations, the metal halide and metal‐water stretchings, and also the librations of the MX_2⋅4H_2O octahedra, have been identified and assigned. |
BibTeX:
@article{Agullo-Rueda87b,
author = {Agulló-Rueda, F. and J. M. Calleja and M. Martini and G. Spinolo and F. Cariati},
title = {Raman and Infrared Spectra of Transition Metal Halide Hexahydrates},
journal = {J. Raman Spectros.},
year = {1987},
volume = {18},
number = {7},
pages = {485--491},
url = {http://dx.doi.org/10.1002/jrs.1250180707},
doi = {10.1002/jrs.1250180707}
}
|
| Garc\ia-Solé J, Agulló-Rueda F, López C, Vergara G, Meseguer F and Calderón T (1987), "Optical Properties of Natural PbCO_3 Single Crystals", Cryst. Latt. Def. and Amorph. Mat.. Vol. 16, pp. 365-370.
[BibTeX] |
BibTeX:
@article{Garcia-Sole87,
author = {Garc\ia-Solé, J. and F. Agulló-Rueda and C. López and G. Vergara and F. Meseguer and T. Calderón},
title = {Optical Properties of Natural PbCO_3 Single Crystals},
journal = {Cryst. Latt. Def. and Amorph. Mat.},
year = {1987},
volume = {16},
pages = {365--370}
}
|
| Mart\inez JL, Agulló-Rueda F and Schmidt VH (1987), "Raman Scattering Study of Rb_1- x(ND_4)_xD_2PO_4 Mixed Crystal", Ferroelectrics. Vol. 76(1), pp. 23-32. |
| Abstract: Raman-scattering spectra of a 71.4% deuterated crystal of Rb_0.52(ND4)_0.48D_2PO_4 were studied in a wide range of temperatures down to 5 K. At low temperatures the system forms a so-called glass state, with no long range order transition to either a ferroelectric or antiferroelectric phase.We have concentrated our study on the vibrations related to the internal modes of the molecular groups (phosphate and ammonium). Special attention is focused on the 2 (symmetric deformation mode) of the PO_4 and the libration mode of the ammonia, because they are very sensitive to the ordering of the protons, and to the ferroelectric- or antiferroelectric-like ordering for the former and the glass-like arrangement for the latter. |
BibTeX:
@article{Martinez87,
author = {Mart\inez, J. L. and F. Agulló-Rueda and V. H. Schmidt},
title = {Raman Scattering Study of Rb_1- x(ND_4)_xD_2PO_4 Mixed Crystal},
journal = {Ferroelectrics},
year = {1987},
volume = {76},
number = {1},
pages = {23--32},
url = {http://dx.doi.org/10.1080/00150198708009020},
doi = {10.1080/00150198708009020}
}
|
| Palacios F, Bartolomé J, Agulló-Rueda F, Calleja JM, Cardona M, Syassen K and Stroessner K (1987), "Spectroscopic Raman study of trifluoroperovskites of ammonium under high pressure", In Quantum Aspects of Molecular Motions in Solids. Berlin , pp. 38-41. Springer. |
| Abstract: The compounds NH_4MF_3 (M = Mg, Zn, Co, Mn, Cd) have the cubic perovskite structure at high temperature, distorting to quasi-tetragonal symmetry at lower temperatures (fig. 1). In a previous communication /1/, some discrepancies between the electrostatic model and experimental data were discussed, mainly the high barrier (2000 K) to rotation of NH_4 groups in NH_4CdF_3. |
BibTeX:
@incollection{Palacios87,
author = {F. Palacios and J. Bartolomé and F. Agulló-Rueda and J. M. Calleja and M. Cardona and K. Syassen and K. Stroessner},
editor = {A. Heidemann and A. Magerl and D. Richter and M. Prager and T. Springer},
title = {Spectroscopic Raman study of trifluoroperovskites of ammonium under high pressure},
booktitle = {Quantum Aspects of Molecular Motions in Solids},
publisher = {Springer},
year = {1987},
pages = {38--41},
url = {http://dx.doi.org/10.1007/978-3-642-71914-1_7},
doi = {10.1007/978-3-642-71914-1_7}
}
|
| Agulló-Rueda F (1986), "Espectroscop\ia Raman de cristales con grupos moleculares: NH_4MX_3 y MX_2 ⋅ 6H_2O [Raman Spectroscopy of Crystals with Molecular Groups: NH_4MX_3 and MX_2 ⋅ 6H_2O]". Thesis at: Autonomous University of Madrid. Madrid |
| Abstract: La presente tesis es un exhaustivo trabajo sobre propiedades estructurales y vibraciones del ion amonio en perovskitas cúbicas y de la molécula de agua en hidratos de metales de transición. Se han determinado la simetr\ia y las frecuencias de los modos de vibración en las distintas fases incluyendo efectos de puente de hidrógeno volumen y resonancia de Fermi. Para ello se ha utilizado la espectroscopia Raman junto con técnicas de presión hidrostática en celda de diamante y absorción óptica. Como resultado se dan valores numéricos de algunos parámetros fundamentales relacionados con la dinámica interna de estos grupos moleculares que eran desconocidos hasta la fecha.\br>This thesis is an exhaustive work on the structural properties and vibrations of the ammonium ion in cubic perovskites and the water molecule in transition metal hydrates. Symmetry and frequencies of vibrational modes have been determined at different phases including volume hydrogen bridge effects and Fermi resonance. Raman spectroscopy has been used in conjunction with hydrostatic pressure techniques in a diamond cell and optical absorption. As a result, numerical values of some fundamental parameters related to the internal dynamics of these molecular groups, which were unknown to date, are given. |
BibTeX:
@phdthesis{Agullo-Rueda1986PHD,
author = {Agulló-Rueda, Fernando},
title = {Espectroscop\ia Raman de cristales con grupos moleculares: NH_4MX_3 y MX_2 ⋅ 6H_2O [Raman Spectroscopy of Crystals with Molecular Groups: NH_4MX_3 and MX_2 ⋅ 6H_2O]},
school = {Autonomous University of Madrid},
year = {1986},
url = {https://www.educacion.gob.es/teseo/mostrarRef.do?ref=50463}
}
|
| Agulló-Rueda F, Calleja JM, Jaque F and Tornero JD (1986), "Absorption Spectra of NH_4MnCl_3 and NH_4MnF_3", Solid State Commun.. Vol. 60(4), pp. 331-335. |
| Abstract: The absorption spectra of NH_4MnCl_3 and NH_4MnF_3 crystals have been measured down to 10 K in the 250 to 600 nm region. The observed bands are assigned to electronic transitions from the ^6A_1g(S) ground state to various excited levels of Mn^2+ ions in an octahedral crystalline field. The position of the bands have been fitted within the strong crystal field scheme. Resulting parameters at room temperature are B = 741, C = 2990 and Dq = 520 cm^-1 for NH_4MnCl_3 and B = 800, C = 3139 and Dq = 694 cm^-1 for NH_4MnF_3. At low temperature some bands show a rich fine structure in which some phonon progressions have been identified. |
BibTeX:
@article{Agullo-Rueda86,
author = {Agulló-Rueda, F. and J. M. Calleja and F. Jaque and J. D. Tornero},
title = {Absorption Spectra of NH_4MnCl_3 and NH_4MnF_3},
journal = {Solid State Commun.},
year = {1986},
volume = {60},
number = {4},
pages = {331--335},
url = {http://dx.doi.org/10.1016/0038-1098(86)90744-1},
doi = {10.1016/0038-1098(86)90744-1}
}
|
| Bartolomé J, Palacio F, Calleja JM, Agulló-Rueda F, Tornero JD, Cardona M and Migoni R (1986), "Dynamics of the NH_4^+ Ion in ABX_3 Perovskites", J. Mol. Struct.. Vol. 143, pp. 75-78. |
| Abstract: The Raman and IR spectra of NH_4MnF_3, NH_4ZnF_3 and NH_4MnCl_3 have been measured in order to study the internal vibration modes of NH_4^+ in different surrounding conditions. The internal force constants have been determined and compared to their values in ammonium halides and in the free ion, Their trends have been discussed in terms of the hydrogen bonding and volume effects. The intraionic polarizability parameters have also been obtained and compared to those of CH_4. |
BibTeX:
@article{Bartolome86,
author = {Bartolomé, J. and Palacio, F. and Calleja, J. M. and Agulló-Rueda, F. and Tornero, J. D. and Cardona, M. and Migoni, R.},
title = {Dynamics of the NH_4^+ Ion in ABX_3 Perovskites},
journal = {J. Mol. Struct.},
year = {1986},
volume = {143},
pages = {75--78},
url = {http://dx.doi.org/10.1016/0022-2860(86)85208-5},
doi = {10.1016/0022-2860(86)85208-5}
}
|