Defect generation in layer-by-layer-grown ZnSe films on Te-terminated GaAs(001) surfaces

We have studied the effect of the Te termination of the GaAs(001) surface on the growth mode and defect generation in the heteroepitaxy of ZnSe. High densities of faulted defects are generated in the ZnSe film grown in a layer-by-layer mode on the Te-terminated GaAs surface, relating closely to the formation of a thin Ga2Te3-like interface layer. The defect density was found to increase with substrate temperature for an exposure of Te on GaAs(001) up to 500 degrees C. However, the defect generation is suppressed by thermal annealing at a higher temperature prior to the ZnSe growth, which is ascribed to the change in the surface reconstruction of Te-terminated GaAs(100) caused by the annealing.