Materials science communication (100) or (111) heteroepitaxy of cdte layers on (100) gaas substrates by organometallic vapor phase epitaxy

Abstract

Systematic studies have been conducted on the growth mechanism of (100) or (111) CdTe on (100) GaAs substrates. No native oxide was observed between the CdTe epilayer and GaAs substrate as proved by high resolution transmission electron microscopy. The orientation of CdTe layer grown on (100) GaAs is only related to the growth conditions. Under normal growth conditions, (100) CdTe is preferred on (100) GaAs substrate under Cd-rich growth conditions. Under Te-stabilized growth conditions, only (100) was observed if no substrate prebake step was used. However, (111) layers were formed if the substrates were baked to high temperature before growth. To confirm only (100) growth, atomic layer epitaxy was used as an initial nucleation step. The crystalline quality of (100) layer can be further improved using thermal cycle growth.