A self-driven and high-performance photodetector based on a GeSe/Si van der Waals heterojunction with high-speed photoresponse.

van der Waals (vdW) heterojunction photodetectors exhibit high performance due to their high-quality interface and high design flexibility, and unique properties of two-dimensional (2D) materials. Particularly, combining 2D semiconductors with technologically mature semiconductors offers a promising pathway toward high-performance photodetection. Herein, we report a high-performance self-driven photodetector based on a vertical GeSe/Si vdW heterojunction, constructed using high-quality GeSe single crystals grown by the chemical vapor transport method, which benefits from the type-II band alignment and the strong built-in electric field at the GeSe/Si interface. As a result, the photodetector exhibits a high responsivity of 29.8 A W-1, a high EQE of 6959.7%, a high detectivity of 2.1 × 1012 Jones, and a fast rise/decay time of 8.5 µs/23.7 µs under 532 nm laser illumination at zero bias. In addition, the GeSe/Si vdW heterojunction photodetectors demonstrate a stable broadband photoresponse and pronounced photovoltaic behavior under visible-light illumination (405-604 nm). This work highlights the advantages of integrating 2D GeSe with silicon via vdW heterojunction engineering and provides a significant strategy for developing self-driven, high-performance photodetectors toward practical optoelectronic applications.