High Performance Self‐Powered and Vis–Infrared Broadband Photodetectors Based on MoTe₂/InSe Van der Waals Heterostructure

Abstract Self‐powered and broadband photodetectors have important applications in modern technologies and have garnered significant research interest with the increasing concern for green and energy‐saving. The emerging 2D materials InSe is considered to be a promising candidate for next‐generation photodetectors due to the high carrier mobility, excellent photoelectric response, and flexibility. However, due to its weak absorption of infrared light, it remains a challenging task to achieve high‐performance, self‐powered, and broadband photodetection. Here, a MoTe₂/InSe van der Waals heterostructure (vdWH) device is successfully constructed. Benefiting from the unique band alignment of the heterostructure, a strong built‐in electric field is formed. Excitingly, the device exhibits excellent photovoltaic performance with a large open voltage and short circuit current of 390.19 mV and 20.32 nA, respectively. In particular, in self‐powered mode, the responsivity (R) is up to 433.88 mA W⁻¹ and the specific detectivity (D*) reaches 1.65 × 10¹² Jones under 405 nm irradiation. Meanwhile, an ultrahigh I_light/I_dark ratio over 10⁴, a fast response speed of 99/117 µs, and a broadband photoresponse range from 405 to 980 nm are achieved. The device demonstrates excellent comprehensive self‐powered photodetection performance. This work reveals the great potential of the MoTe₂/InSe vdWH for high‐performance, broadband, and self‐powered photodetection.