Abstract
We have studied the interband transitions from undoped and modulation-doped As/AlAs multiple-quantum-well structures (the latter were doped n type in the As layers). Two types of transitions have been observed: Type I associated with electron-hole recombination in the As layers and type II between electrons in the and valleys of the AlAs layers and holes confined in the As layers. In undoped samples the luminescence associated with type-II transitions is dominated by phonon replicas. In contrast, the intensities of the zero-phonon and transitions in modulation-doped samples are comparable to those of the replicas. Under optical pumping the type-II transitions in undoped samples show a pronounced blueshift due to band bending. Under high pumping intensity, the spectra from the undoped samples strongly resemble those from the modulation-doped structures. © 1996 The American Physical Society.
- Received 9 February 1996
DOI:https://doi.org/10.1103/PhysRevB.53.12912
©1996 American Physical Society