Kronig-Penney-like description for band gap variation in SiC polytypes

Abstract

A one-dimensional Kronig-Penney-like model for envelope wave functions is presented to explain the band gap variation of SiC polytypes. In this model the envelope functions obey discontinuous boundary conditions. The electronic band gaps of cubic and several hexagonal and rhombohedral SiC polytypes are calculated. The polytypic superlattices are assumed to be stackings of differently sized and orientated cubic SiC segments. The empirical Choyke-Hamilton-Patrick relation is understood and deviating trends for small hexagonalities and rhombohedral modifications are predicted.