Growth of ZnO thin film on p-GaN/sapphire (0 0 0 1) by simple hydrothermal technique

Zinc oxide (ZnO) heteroepitaxial thin films were successfully grown on p-GaN/sapphire (0 0 0 1) by single-step hydrothermal route at a low temperature of 90 °C. Continuous ZnO thin films with c-axis orientation were grown in aqueous solution of zinc acetate di-hydrate and ammonium hydroxide. X-ray diffraction, scanning electron microscopy and room temperature photoluminescence were carried out for structural, morphological and optical property analysis. The as-grown ZnO films showed preferential growth along (0 0 0 1) direction. The in-plane orientation between ZnO thin film and p-GaN buffer layer was found to be [1 1 2¯ 0]ZnO∥[1 1 2¯ 0]GaN. Sharp luminescence peak centered at 377 nm due to excitonic recombination from ZnO thin film was observed.