MOLECULAR-BEAM EPITAXIAL-GROWTH MECHANISM OF ZNSE EPILAYERS ON (100) GAAS AS DETERMINED BY REFLECTION HIGH-ENERGY ELECTRON-DIFFRACTION, TRANSMISSION ELECTRON-MICROSCOPY AND X-RAY-DIFFRACTION

The properties of molecular beam epitaxial growth of ZnSe epilayers de posited directly on a GaAs substrate are compared to those grown on a GaAs buffer layer. The superior quality of the latter is confirmed by RHEED, TEM and X-ray diffraction. Based on RHEED oscillation studies, a model explaining the dependence of the ZnSe growth rate on Zn and Se fluxes and the substrate temperature is developed taking into account physi- and chemisorbed states. For partially relaxed epilayers, the c orrelation between the relaxation state and the crystalline mosaicity, as found by high resolution X-ray diffraction, is discussed.