A self-powered solar-blind ultraviolet photodetector based on a Ag/ZnMgO/ZnO structure with fast response speed

A self-powered solar-blind ultraviolet (UV) photodetector was realized on a Ag/ZnMgO/ZnO vertical structure. A ZnO epitaxial layer was employed to serve as both the buffer layer for the growth of ZnMgO and the bottom electrode of the device. Interestingly, the device exhibited an obvious self-powered property owing to the built-in electric fields at the Ag/ZnMgO and ZnMgO/ZnO interfaces. At 0 V, the peak responsivity at 275 nm of our device was 16 mA W-1, which is comparable to that of other ZnMgO self-powered solar-blind UV photodetectors. Moreover, the device also exhibited a very fast response speed (24 mu s rise time and 300 mu s decay time) at 0 V. This study could provide a much easier and more feasible way to develop ZnMgO self-powered solar-blind UV photodetectors on foreign substrates with high responsivity, fast response speed, and low cost.