A self-powered Ag/β-Ga2O3 photodetector with broadband response from 200 to 980 nm based on the photovoltaic and pyro-phototronic effects

Abstract

β-Ga2O3, as one of the important 4th generation semiconductors, is widely used in solar-blind ultraviolet (UV) detectors with a short detection range of 200–280 nm benefiting from its ultra-wide bandgap, strong radiation resistance, and excellent chemical and thermal stabilities. Here, a self-powered photodetector (PD) based on an Ag/β-Ga2O3 Schottky heterojunction was designed and fabricated. Through a subtle design of electrodes, the pyro-phototronic effect was discovered, which can be coupled to the common photovoltaic effect and further enhance the performance of the PD. Compared to traditional Ga2O3-based PD, the as-used PD exhibited a self-driving property and a broadband response beyond the bandgap limitations, ranging from 200 nm (deep UV) to 980 nm (infrared). Moreover, the photoresponse time was greatly shrunk owing to the coupling effect. Under laser irradiation, with a wavelength of 450 nm and a power density of 8 mW cm‒2, the photocurrent could be improved by around 41 times compared with the sole photovoltaic effect. Besides, the performances of the Schottky PD were enhanced at both high and low temperatures. The device also possessed long-term working stability. This paper not only reveals basic physics lying in the 4th generation semiconductor Ga2O3 but also sheds light on the multi-encryption transmission of light information using this PD.