Fabrication of nonpolar ZnO film on γ-LiAlO2 substrate and its photo-luminescence properties

Nonpolar a-plane (1120) ZnO films were successfully grown on (302) γ-LiAlO2 substrate by pulsed laser deposition. When the temperature of the substrate was 350℃, the film was mix-oriented(a and c) with a wide distribution of crystal grain size, and the c-plane ZnO was dominant. When the temperature of the substrate was 500℃, pure (1120) ZnO film was formed，with the FWHM of ZnO (1120) rocking curve ～0.65° and the grain size distribution narrowed. Its in-plane anisotropy was demonstrated by polarized transmission spectrum. The FWHM of the peak of near band emission in the PL spectra was found to be only 105meV for the sample with substrate temperature of 650℃，indicating the large size and uniform distribution of crystal grains which was also confirmed by AFM.