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 significantly stronger than in comparable microcavities that contain quantum wells solely at …
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 …
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 …
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 …
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 Å/(40 Å) GaAs/(GaAl)As superlattice, determined from low-temperature …
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, $\cal{E}$, decrease, reaching at least …
We have observed electric-field-induced interactions between the extended states of a (40 Å)-(15 Å) 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 …
We have shown that the coherence length of electrons in a 55-Å-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 …
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, …