High-quality CdTe growth in the (100)-orientation on (100)-GaAs substrates by molecular beam epitaxy

This paper describes molecular beam epitaxial growth of high-quality CdTe films in the (1 0 0)-orientation on (1 0 0)-GaAs substrates. It is revealed by a photoluminescence measurement that a defect-related emission band is dominant when the CdTe film is directly grown on the GaAs substrate. After applying a postgrowth annealing, however, the crystalline quality of the CdTe film is improved to exhibit a reduced defect-related emission band and an intense emission peak from excitons. Although the CdTe surface after annealing is rough due to the formation of thermal etchpits, a MnTe capping prior to the annealing is found to be effective to keep the surface smooth. The usefulness of this method is demonstrated by applying the annealed MnTe/CdTe film as a buffer layer for high-quality CdTe overgrowth. (C) 2001 Elsevier Science B.V. All rights reserved.