Local irradiation effects of one-dimensional ZnO based self-powered asymmetric Schottky barrier UV photodetector

Abstract A self-powered metal-semiconductor-metal (MSM) UV photodetector was successfully fabricated based on Ag/ZnO/Au structure with asymmetric Schottky barriers. This exhibits excellent performance compared to many previous studies. Very high photo-to-dark current ratio (approximately 10 5 –10 6 ) was demonstrated without applying any external bias, and very fast switching time of less than 30 ms was observed during the investigation. Opposite photocurrent direction was generated by irradiating different Schottky diodes in the fabricated photodetector. Furthermore, the device performance was optimized by largely irradiating both the ZnO microwire (MW) junctions. Schottky barrier effect theory and O 2 adsorption–desorption theories were used to investigate the phenomenon. The device has potential applications in self-powered UV detection field and can be used as electrical power source for electronic, optoelectronic and mechanical devices.