Energy levels of very shorthyphen;period (GaAs)nhyphen;(AlAs)nsuperlattices

摘要

The energy levels of very shorthyphen;period (GaAs)nhyphen;(AlAs)nsuperlattices (nle;4) were investigated by photoluminescence (PL). The results show that these superlattices are type II but the lowest conduction bands areXx,yfornle;3 andXzforn=4, respectively. (HereXzis the valley withkparallel to the growth axis.) In both cases theXvalleys are very close to each other. PL decay, PL excitation, and PL under uniaxial stress confirm this identification. Al0.5Ga0.5As shows very different behavior, showing that even forn=1 our samples are true superlattices.