Self-Powered Broadband Photodetector Based on MoSe2/SnS2 Van der Waals Heterostructure

The increasing demand for broadband and self-powered optoelectronic devices has stimulated the development of two-dimensional (2D) material-based photodetectors. Here, we construct a self-powered photodetector based on a MoSe2/SnS2 van der Waals (vdW) heterostructure. The unique combination of MoSe2 and SnS2 provides complementary light absorption and a type-II band alignment, which generates an interfacial built-in electric field to facilitate photogenerated carrier separation and transport, enabling efficient self-powered operation without external bias. The device exhibits a broad spectral photoresponse from ultraviolet (UV) to infrared (IR) wavelengths (350–1050 nm). Under zero bias, the photodetector achieves a responsivity of 0.6 mA/W and a rapid response time of 5.8/6.1 ms (rise/fall) under 405 nm illumination, demonstrating effective self-driven photoresponse. With an applied reverse bias of −2 V, the device further reaches a responsivity of 161 mA/W and a detectivity of 8.6 × 1010 Jones under 405 nm illumination. In addition, the device exhibits a low dark current of 5 pA and a high on/off ratio of 1180. These results demonstrate the potential of the MoSe2/SnS2 vdW heterostructure for broadband and self-powered optoelectronic applications.