A wire-shaped photoanode of the solar-blind photoelectrochemical-type photodetector based on an α-Ga₂O₃ nanorods/electrolyte solid/liquid heterojunction

Multifunctional and smart solar-blind photodetectors are of great significance for many applications, particularly for communications, optoelectronic circuits, and environmental risk monitoring. In this study, a wire-shaped photoanode of the solar-blind photoelectrochemical (PEC)-type photodetector based on an α-Ga₂O₃ nanorods/electrolyte solid/liquid heterojunction is realized. In photovoltaic devices, a junction generally comprises two different solid materials to facilitate the separation of photogenerated electron–hole pairs. Similarly, a solid/liquid junction is formed between the semiconductor and the electrolyte in a PEC photodetector. The apparent rectification characteristics of the dark current indicate that the energy bands bend at the α-Ga₂O₃ nanorods/electrolyte interface. The local electric field in the semiconductor effectively promotes the separation of carriers. The photodetectors exhibit a high light/dark current ratio (I_light/I_dark) of 68.7; fast rise and decay response times of 0.1 and 0.06 s, respectively; and a high responsivity of 11.2 mA/W (@230 nm) at zero bias. The wire-shaped photoanode is beneficial for realizing potential omnidirectional solar-blind detection.