Self-Powered Solar-Blind Photodetectors Based on α-Ga₂O₃ Nanorod Arrays

Low power consumption, high sensitivity, and miniaturization of photodetectors are important features in future photonic systems. Therefore, photoelectrochemical-type photodetectors with an independent power supply, high performance, and compact structure have attracted great interest in recent years. However, the development of a photoelectrochemical-type photodetector with excellent crystal quality and sufficient contact area between nanorod arrays and the electrolyte environment remains a challenge. In this work, a self-powered and solar-blind photodetector based on α-Ga2O3 nanorod arrays in a photoelectrochemical unit structure was fabricated, and the α-Ga2O3 nanorod arrays were synthesized by a short-term-reaction and ultra-low-cost hydrothermal route. The prepared self-powered photodetector has superior photoresponsivity of 3.87 mA/W, a high Iphoto/Idark ratio of 12.81, and photoresponse rise and decay times of 0.23 and 0.15 s, respectively, under 254 nm deep ultraviolet light with a light intensity of 3.0 mW/cm2, which are better than those of reported α-Ga2O3 based photodetectors. The superb crystal quality of the α-Ga2O3 nanorod arrays, which provides a fast passage for photogenerated carrier transport, and the effective separation of photogenerated electron–hole pairs controlled by the built-in electric field of the semiconductor/electrolyte solid–liquid heterojunction interface are largely responsible for the outstanding performance of our photodetector. Undoubtedly, self-powered and energy-efficient device proposed in our work is a promising candidate for solar-blind photodetector applications.