Interfacial Engineering of SnS/Ga2O3 Heterojunction by SnO for a High‐Performance Self‐Powered Solar‐Blind UV Photodetector

Abstract A novel self‐powered deep ultraviolet (UV) photodetector based on a SnS/Ga2O3 heterojunction modified by an ultrathin SnO layer has been developed by the pulse laser deposition method. Under 254 nm UV light at 170 µW cm−2, the device demonstrates remarkable photoelectric performance with a low dark current of 42 fA, a high photo‐to‐dark current (Iphoto/Idark) ratio of 3.81 × 103, a specific detectivity (D*) of 2.56 × 1011 Jones, and a quick rise/decay time of 31/64 ms without any power supply, thanks to the SnO interfacial layer. The SnS/SnO/Ga2O3 heterojunction photodetector has substantially superior self‐powered properties than the corresponding SnS/Ga2O3 device. This can be explained by the mechanisms of interface energy band engineering and the tunneling effect. The SnO layer broadens the depletion zone and facilitates charge separation. Due to the thinness of the SnO layer, charges can also tunnel through it. These accomplishments set the stage for future optoelectronic applications of Ga2O3 solar‐blind UV photodetectors that are self‐powered.