Electric fields and valence-band offsets in n+n [001] and [110] ZnSe/GaAs, GaAs/Ge, and ZnSe/Ge superlattices

Abstract

Results for n+n [001] and [110] (n=1–5) ZnSe/GaAs, GaAs/Ge, and ZnSe/Ge superlattices obtained from self-consistent calculations with the augmented-spherical-wave ab initio band-structure method are presented. The valence-band offsets are calculated with the frozen-potential method and compared with those obtained with a new method that is based on the shifts of the potentials of the individual atoms. The internal electric fields that result from the charge separation at the interfaces in the polar [001] superlattices is calculated, and its origin is traced. The valence-band offset is shown to be not affected by these fields.