Broadband high-performance vertical WSSe/Si heterojunction photodetector with MXene electrode.

Vertical semiconductor van der Waals heterojunctions are essential for fabricating high-performance photodetectors. However, the range of the spectral response and defect states of semiconductor materials are two critical factors affecting the performance of photodetectors. In this work, the spectral response range of WSwas changed through WSband gap regulation, and a self-powered vertical WSSe/Si heterojunction photodetector with MXene electrode was prepared by synthesizing WSSefilm on Si substrate and vertically stacking TiCTMXene on the film. Due to the electron collection of MXene and the wonderful junction quality of WSSe/Si, the photodetector can detect near-infrared light in the range of 980-1310 nm, which exceed the detection limit of WSSe. And the device had high sensitivity in the broadband. The responsivity was 4.58 A W, the specific detectivity was 4.58 × 10Jones, the on/off ratio was 4.95 × 10, and the fast response time was 9.81/9.03s. These properties are superior to previously reported WS-based photodetectors. Vertical structure, Energy band tuning, and MXene electrode provide a new idea for preparing broadband high-performance and self-powered photodetector.