Growth of ZnO(0 0 2) and ZnO(1 0 0) films on GaAs substrates by MOCVD

ZnO films were grown on GaAs(0 0 1)substrates at different surface treatment conditions at different growth temperatures by metal-organic chemical vapor deposition. ZnO(1 0 0) and ZnO(0 0 2) films that had different preferred orientations were grown according to different chemical etching condition. The crystallinity and optical properties of ZnO films were investigated with X-ray diffraction and the room-temperature photoluminescence spectra. Compared with ZnO(0 0 2) films, ZnO(1 0 0) films that have undergone variation at the preferred orientation have better crystal structure. Moreover, all samples have similar optical characteristics at the same growth temperature. For GaAs substrates etched under different conditions, the analysis results of X-ray photoelectroscopy show that the preferred orientation variations of ZnO films take place because rich As layer are formed in process of chemical etching.