Self-Powered Solar-Blind Photodetectors Based on Vertically Aligned GaN@Ga₂O₃ Core–Shell Nanowire Arrays

The self-powered photodetector has recently received wide attention as a fundamental component of energy-saving optoelectronic systems. In this study, the GaN@Ga2O3 core–shell nanowire arrays (NAs) were used as the photoanode for the self-powered solar-blind photoelectrochemical-type photodetectors (PEC-PDs). The vertically aligned GaN@Ga2O3 core–shell NAs on the GaN template was fabricated by the inductively coupled plasma etching combined with the thermal oxidation process. Under 255 nm illumination without an external power supply, the device exhibits a maximum responsivity of 93.48 mA/W, yielding a high external quantum efficiency of 45.54%, which shows one of the best values among the reported solar-blind Ga2O3-based PEC-PDs. Furthermore, the device shows a fast response speed (τr = 25 ms, τd = 5 ms) and good stability. Such excellent performance under zero bias may benefit from the superior light-absorbing capability of the vertical NAs, the good solid/liquid contact realized by the nanostructures, and the efficient photogenerated carrier separation driven by the double built-in electric field. This work provides a simple and feasible route to construct high-performance solar-blind Ga2O3-based PEC-PDs.