Barrier-width dependence of optical transitions involving unconfined energy states in GaAs-As superlattices
- 15 December 1986
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 34 (12), 8958-8962
- https://doi.org/10.1103/physrevb.34.8958
Abstract
Optical transitions between confined electron and hole states in GaAs- As superlattices have been studied extensively. Transitions involving unconfined states, i.e., states above the conduction- or below the valence-band barriers, have not received much attention. Here, we report the results of photoluminescence-excitation spectroscopy in the energy range of the unconfined transitions. We find a variety of structures in the spectra, which can be interpreted with the aid of theoretically generated absorption spectra. The strength of the transition involving the first unconfined heavy-hole to first unconfined conduction state is found to depend strongly on the barrier width. For superlattices with 150-Å wells and barriers with aluminum concentrations of 20%, the transition is very strong for 150-Å barriers, but insignificant for barrier widths of 70 and 30 Å. Transitions involving the split-off valence bands are also observed.
Keywords
This publication has 8 references indexed in Scilit:
- New Optical Characterization Methods Of Molecular Beam Epitaxy-Grown Multi-Quantum-Well Structures Using Tunable Light SourcesPublished by SPIE-Intl Soc Optical Eng ,1986
- Confined electron states in GaAs-Ga1-xAlxAs (0.2⩽x⩽1.0) superlatticesJournal of Physics C: Solid State Physics, 1986
- New evidence of extensive valence-band mixing in GaAs quantum wells through excitation photoluminescence studiesPhysical Review B, 1985
- GaAs, AlAs, and AlxGa1−xAs: Material parameters for use in research and device applicationsJournal of Applied Physics, 1985
- Band mixing in semiconductor superlatticesPhysical Review B, 1985
- Delocalized excitons in semiconductor heterostructuresPhysical Review B, 1984
- Observation of Superlattice Effects on the Electronic Bands of Multilayer HeterostructuresPhysical Review Letters, 1981
- InAs-GaSb superlattice energy structure and its semiconductor-semimetal transitionPhysical Review B, 1978