In the present work, a new type of self-powered photoelectrochemical (PEC) solar-blind ultraviolet (UV) photodetector has been constructed using alpha-gallium oxide/tantalum (α-Ga 2 O 3 /Ta) as photoanode. The photoelectric properties of the device have been investigated systematically. Under zero-bias conditions with 254 nm UV light illumination, the α-Ga 2 O 3 /Ta PEC photodetector achieves a responsivity of 6.6 mA/W, an external quantum efficiency of 3.22%, a high light/dark current ratio of 546.5, a rise/decay time of 0.37 s/0.07 s, and a specific detectivity of 1.46 × 10 12 Jones, exhibiting typical solar-blind UV response characteristics and stable self-powered ability. The outstanding performance of the α-Ga 2 O 3 /Ta PEC photodetector is mainly attributed to the built-in electric field resulted from the solid-liquid interface, which can effectively separate photogenerated electron-hole pairs and promote the self-driven ability of the device. More importantly, the adoption of thermally stable Ta substrate significantly enhances the crystalline quality of α-Ga 2 O 3 , concurrently reducing dark current and carrier recombination rates. These improvements collectively boost the responsivity, response speed, and long-term operational stability of the α-Ga 2 O 3 /Ta PEC photodetector, making it potentially suitable for harsh-environment applications including high-temperature and acidic conditions.
Liu et al. (Mon,) studied this question.