Stable and Self-Powered Solar-Blind Ultraviolet Photodetectors Based on a Cs3Cu2I5/β-Ga2O3 Heterojunction Prepared by Dual-Source Vapor Codeposition

Self-powered solar-blind ultraviolet (UV) photodetectors have drawn worldwide attention in recent years because of their important applications in military and civilian areas. In this study, a dual -source vapor codeposition technique was employed, for the first time, to prepare a nontoxic copper halide Cs3Cu,I-5, which was integrated with the fi-Ga2O3 wafer to construct a type -II heterojunction for photodetection applications. By optimizing the annealing conditions, high -quality Cs3Cu,I-5 films with dense morphology, high crystallinity, and a long carrier lifetime of 1.02 s were acquired. Because of the high material integrity of Cs3Cu,I5 films and effective interfacial carrier transfer from Cs3Cu,I-5 to fi-Ga,03, a heterojunction device demonstrates a good solar -blind UV response property and operates at zero bias. Typically, the photodetector presents a low dark current (similar to 1.2 pA), a high solar -blind/ UVA rejection ratio (similar to 1.0 X 10(3)), a relatively fast photoresponse speed (37/45 ms), and a high photo -to -dark current ratio (similar to 5.1 X 10(4)) at zero bias. Moreover, even after 12-h continuous working and 2 -month storage without encapsulation in ambient air, the photodetection ability of the device can almost be maintained, demonstrating outstanding air stability. Our results suggest that nontoxic Cs3Cu,I-5 is able to serve as a prospective candidate for stable solar-blind UV photodetection.