Wurtzite GaN film was grown on c-plane sapphire substrate by hydrogen vapor phase epitaxy (HVPE) method , GaN nano wires and nanoflowers grown on sapphire substrate were obtainedthrough a simple chemical vapor deposition (CVD) process, asdescribed in our previous work [24]. The phase and purity ofas-grown GaN nanostructures were examined by a Rigaku RINT2000 X-ray powder diffractometer (XRD) with Cu Kradiation,operating at 40 kV and 40 mA. The morphology and composi-tion of GaN samples were characterized by scanning electronmicroscope (SEM INSPECT, F50) attached X-ray diffraction spec-trometer (EDS) and a Dektak XT stylus profiler, respectively. Thesurface resistivity of the GaN film was measured by four-point-probe resistivity measurement system (RTS-9).