Structural Properties of ZnO Grown on GaN∕Sapphire Templates

Abstract

ZnO nanorods were synthesized on GaN/sapphire substrates using a modified thermal-evaporation process. The as-synthesized ZnO nanorods and thin films were characterized using scanning electron microscopy, micro-Raman, and X-ray diffraction techniques. The morphology of the ZnO changes from nanorods to continuous thin films when the growth temperature increases to 800°C. Further increase in the growth temperature leads to a lower growth rate of ZnO along the (0001) direction. Micro-photoluminescence measurements show ultraviolet band-edge emission peaks around 378 nm from both nanorods and thin films. Realization of such ZnO structures may be useful for the fabrication of hybrid ZnO/GaN optoelectronic devices.