The strain, energy band and photoluminescence of GaAs0.92Sb0·08/Al0.3Ga0.7As multiple quantum wells grown on GaAs substrate

Abstract

GaAsSb based materials have become the promising system for infrared semiconductor lasers and detectors. In this article, the strain, energy band structures and photoluminescence (PL) of GaAs0.92Sb0·08/Al0.3Ga0.7As strained quantum wells (QWs) grown with molecular beam epitaxy are systematically analyzed both theoretically and experimentally. The theoretical results are derived by Kane's model and k⋅p method, and the optical properties of a high-quality GaAs0.92Sb0·08/Al0.3Ga0.7As strained QWs sample are thoroughly investigated by excitation- and temperature-dependent PL measurements. The theoretical results show the strain has significant influence on the band structure of QWs. In experimental part, it is found that the light-hole exciton emission coexists with the heavy-hole exciton line in the temperature range of 50 K–300 K. However, the emission of localized excitons, which is caused by the nonuniformity of component in the GaAsSb well layer, takes over the light-hole exciton emission at lower temperatures (<50 K).