EFFECTS OF INTERFACE ATOMIC CONFIGURATIONS ON ELECTRONIC-STRUCTURES OF SEMICONDUCTOR SUPERLATTICES

The electronic structures are calculated using the semiempirical sp3s* tight-binding method for [001] GaAs/ZnSe and GaAs/AlAs semiconductor superlattices which have several structures at the interface. The results of calculation show that in GaAs/ZnSe superlattices electrons and holes are localized around donor (Ga-Se) and acceptor (Zn-As) bonds at the interface, respectively, and that the band-gap energy changes largely (approximately 0.3 eV) with varying configuration of donor and acceptor bonds. In GaAs/AlAs superlattices, because the difference in ionicity between GaAs and AlAs is small, there is little difference in the electronic structures between superlattices with various interface structures.