Performance enhancement of a self-powered solar-blind UV photodetector based on ZnGa2O4/Si heterojunction via interface pyroelectric effect

Abstract

The photodetectors based on the wide bandgap semiconductor (WBS)/Si heterojunction have attracted more and more attention in recent years due to their excellent photoelectric characteristics and easy integration capabilities. In this work, we have demonstrated a self-powered solar-blind ultraviolet (UV) photodetector based on the ZnGa2O4/Si heterojunction. A typical rectification characteristic with a rectification ratio exceeding 103 within ±5 V can be obtained. At 0 V bias, the −3 dB cutoff wavelength of ∼255 nm and the UV-visible rejection ratio of ∼3 × 102 show that the device has excellent self-powered solar-blind UV detection performance. In addition, the responsivity and the response speed of ZnGa2O4/Si heterojunction can be efficiently enhanced by a transient spike current at 0 V bias when turning on and off the 254 nm UV light. The interface pyroelectric effect of the ZnGa2O4 film should be responsible for this transient spike photocurrent phenomenon. Our findings in this work pave a feasible way to realize high-performance WBS/Si heterojunction self-powered solar-blind photodetectors.