Self-Powered Solar-Blind Photodetectors Based on α-Ga<sub>2</sub>O<sub>3</sub> Nanorod Arrays
Baohua Zhang, Huanxing Wu, Cheng Feng, Zheng Zhang, Haibo Yu, Congting Zhang, Shuang Lin, Chang Xu, Haineng Bai, Fuqiang Guo
Abstract
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.