Spectroscopic studies of strained-layer GaSbAlSb superlattices

Photoreflectance (PR) and photoluminescence (PL) studies of GaSbAlSb multiple quantum well structures under hydrostatic pressure at cryogenic temperatures are presented. A large number of excitonic transitions from the conduction sub-hands (CB) to the light (LH) and heavy (HH) hole sub-bands are observed in PR. In contrast, the ground sub-band transition from the CB to the LH dominates the PL. The pressure coefficients get progressively smaller for the higher sub-band transitions. The PL intensity drops dramatically as the direct Γ CB crosses the L CB at ∼ 10 kbar but the PR intensity does not. However a large drop in PR signal is observed as the X CB crosses each sub-band energy. © 1990.