Vertical asymmetric metal-semiconductor-metal photodiode based on -Ga2O3 thin films fabricated via solution process for arc discharge detection

Arc discharge detection is a preeminent strategy for diagnosing aging of high-power electric equipment. Therefore, the timely detection of arc discharge can prevent immense disasters, such as massive fire ac-cidents. Ultraviolet C (UVC) photodetectors (PD) are effective devices for optical arc discharge detection because of their solar blindness, which enables noise-free and highly selective arc discharge detection. In this study, we developed a solution-processed beta-Ga2O3-based vertical asymmetric metal-semiconductor-metal (MSM) UVC PD as a high-performance and inexpensive UVC detector. The high bandgap of photo-active beta-Ga2O3 (4.7-5.1 eV) enables selective UVC detection. The Schottky barrier heights at two different metal-semiconductor junctions (PEDOT:PSS/beta-Ga2O3 and ITO/beta-Ga2O3) were systematically modulated by varying the beta-Ga2O3 film annealing temperature and thickness, which enabled fast photoresponse and self-powered operation, as demonstrated by various optical and electrical analyses. The optimized device ex-hibited a fast photoresponse (rise/fall time of 67/53 ms) and high responsivity (41 mA W-1) and detectivity (1.5x1011 Jones) in self-powered mode. The instantaneous arc discharge was successfully detected using the beta-Ga2O3 based vertical MSM PD, demonstrating its feasibility for arc discharge detection. Thus, this study provides new insights into inexpensive self-powered PDs that can be implemented for the facile and prompt monitoring of aging electric equipment and prevention of potential fire accidents.(c) 2023 Elsevier B.V. All rights reserved.