Influence of twinned structure on the morphology of CdTe(111) layers grown by MOCVD on GaAs(l00) substrates

摘要

The morphology and structure of CdTe(l 1 1) layers grown on GaAs(100) by MOCVD have been studied by atomic force microscopy (AFM) and X-ray texture analysis. Growth conditions have been chosen so that mirror-like CdTe layers are obtained. Layers whose growth times vary between 10s and 2h have been investigated. The X-ray texture analysis shows that the CdTe layers grown on GaAs substrates that were thermally treated at 580℃ for 30 min in a H_2 atmosphere exhibit a (111) preferential orientation and are twinned. This twinned structure of the (11 l)CdTe layer which is observed as 60° rotated triangular crystallites in the AFM images strongly influences the surface morphology. The AFM results have been interpreted using a dynamic scaling theory. The occurrence of a 2D-3D growth transition has been detected after periods of growth in the range of 100-300 s.