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 degrees 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. (c) 2007 The Electrochemical Society.