<i>p</i>-GaSe/<i>n</i>-Ga<sub>2</sub>O<sub>3</sub> van der Waals Heterostructure Photodetector at Solar-Blind Wavelengths with Ultrahigh Responsivity and Detectivity
Yuehui Wang, Yuqing Tang, Haoran Li, Zhibin Yang, Qingyi Zhang, Zhenbei He, Xu Huang, Xianhua Wei, Weihua Tang, Wen Huang, Zhenping Wu
Abstract
Ga2O3 with a suitable bandgap width is emerging to be a novel candidate for future optoelectronic applications in the solar-blind region (<280 nm). Herein, solar-blind photodetectors are developed by combining layered GaSe flakes with Ga2O3 epitaxial films, forming a van der Waals pn heterojunction. Photoresponse characterizations indicate that the GaSe/Ga2O3 pn junction is highly sensitive to solar-blind ultraviolet light, with the maximum sensitivity at ∼255 nm. The photodetector demonstrates a particularly high responsivity of 51.9 A/W, a pronounced specific detectivity up to 1014 Jones, and a fast response speed of ∼0.3 ms under ultraweak light illumination. These figures of merit are significantly superior to most of the reported Ga2O3-based photodetectors. This work reveals the great potential of GaSe/Ga2O3 van der Waals heterojunction for developing next-generation, solar-blind photodetectors.