Abstract: High-quality Mg_xZn_1-xO thin films were grown on sapphire(0001) substrates with a ZnO buffer layer of different thicknesses by means of metal-organic chemical vapor deposition. Diethyl zinc, bis-cyclopentadienyl-Mg and oxygen were used as the precursor materials. The crystalline quality, surface morphologies and optical properties of the Mg_xZn_1-xO films were investigated by X-ray diffraction, atomic force microscopy and photoluminescence spectrometry. It was shown that the quality of the Mg_xZn_1-xO thin films depends on the thickness of the ZnO buffer layer and an Mg_xZn_1-xO thin film with a ZnO buffer layer whose thickness was 20 nm exhibited the best crystal-quality, optical properties and a flat and dense surface.

Key words: Mg_xZn_1-xO, ZnO Buffer layer, Sapphire substrate, MOCVD, AFM