Abstract
GaSb/AlSb multiple-quantum-well structures with well widths ranging from =2 nm to =11.5 nm were studied by means of absorption and excitation spectroscopy. Optical transitions from the quantized ground state n=1, as well as of several higher quantized states (up to n=3), were observed. The distribution of the discontinuity, i.e., the well depth Δ of the valence band and the well depth Δ of the conduction band, is determined from the energy splitting of the light-hole and heavy-hole subbands. We determine the average valence-band discontinuity Δ=350 meV for this system, which is about 23% of the total discontinuity. Strain effects resulting from different lattice constants of GaSb and AlSb increase or lower this value for the light-hole levels or heavy-hole levels, respectively. The discontinuity distribution obtained from absorption and excitation spectroscopy is verified by the analysis of the well-width dependence of the emission energy of direct and indirect recombination in the quantum wells as well as by the well-width dependence of the emission energy of + transitions.
- Received 8 September 1987
DOI:https://doi.org/10.1103/PhysRevB.37.6278
©1988 American Physical Society