The authors report the fabrication of GaN-based metal-semiconductor-metal photodetectors (PDs) on a conventional flat sapphire substrate and on a nanorod template. Compared with the PD prepared on the flat sapphire substrate, it was found that leakage current of the PD prepared on the nanorod template was significantly smaller due to the improved crystal quality. It was also found that we can reduce the photoconductive gain and enhance ultraviolet-to-visible rejection ratio by using the nanorod template.
