Orientational superlattices formed by CuPt-ordered zinc-blende semiconductor alloys

Abstract

We performed a systematic study on a nonconventional semiconductor heterostructure---orientational superlattices (OSL's)---based on CuPt-ordered zinc-blende alloys. Instead of the band offset in conventional superlattices, it is the discontinuity in the angular momentum which brings about the superlattice effects in orientational superlattices. Valence-band structures of five polytypes of OSL"s formed by CuPt-ordered ${\mathrm{GaInP}}_{2}$ layers have been classified according to their symmetries and calculated numerically by using the envelope-function approximation for structures with different periods, ratios of layer thickness, and degree of order. On one hand, features similar to those in conventional superlattices---wave-function modulation, band-gap modification, and the formation of subbands and minigaps---can be achieved purely from an orientational alternation of the semiconductor layers. On the other hand, the dependence of energy levels on layer thickness and the wave-function distributions in OSL's are distinct from that in conventional superlattices.