Photoconductive enhancement of Au nanoparticles-decorated single ZnO nanowire photodetector through formation of local schottky junction

A single ZnO nanowire (NW) photodetector was fabricated and measured under different excitation intensities. The photoconductive internal gain was decreased as the excitation intensity was increased, indicating the hole-trapping photoconduction mechanism of ZnO NWs. As Au nanoparticles are decorated at the surface of a ZnO NW, the local space charge region is formed due to the existence of Schottky junction. This enhancement of the surface electric field results in more pronounced electron-hole separation effect, which then prolongs the lifetime of photogenerated electron and consequently increases the photocurrent. This study provides an easy way to enhance the sensitivity of photodetectors.