Evolution of interfacial properties with annealing in InAs/GaSb superlattice probed by infrared photoluminescence

Abstract

Postgrowth rapid-annealing effects are investigated by infrared photoluminescence (PL) in the InAs/GaSb type-II superlattice (T2SL) with intentional InSb interfaces. The changes in PL energy, linewidth, and integral intensity with temperature indicate that the PL process is dominated by electron–phonon interaction in the InSb-like interfaces and adjacent narrow portions of InAs layers. The interfacial electron level serves as a thermal escape channel for the first miniband electrons and affects the T2SL high-temperature properties. Annealing promotes the interfacial atom exchange and changes the electron thermal escape energy. It transforms the PL-related interfacial regions to InSb1−xAsx at annealing temperatures below 470 °C, activates In/Ga exchange, and transforms the regions to In1−yGaySb at 500 °C. The results indicate that an optimized annealing temperature is crucial for improving the T2SL performance by postgrowth annealing, and infrared PL can serve as an effective criterion for the optimization.