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/Ga 2 O 3 heterojunction modified by an ultrathin SnO layer has been developed by the pulse laser deposition method. Under 254 nm UV light at 170 µ W cm −2 , the device demonstrates remarkable photoelectric performance with a low dark current of 42 fA, a high photo‐to‐dark current ( I photo / I dark ) ratio of 3.81 × 10 3 , a specific detectivity (D*) of 2.56 × 10 11 Jones, and a quick rise/decay time of 31/64 ms without any power supply, thanks to the SnO interfacial layer. The SnS/SnO/Ga 2 O 3 heterojunction photodetector has substantially superior self‐powered properties than the corresponding SnS/Ga 2 O 3 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 Ga 2 O 3 solar‐blind UV photodetectors that are self‐powered.