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

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 x 10(12) Jones under 405 nm irradiation. Meanwhile, an ultrahigh I-light/I-dark ratio over 10(4), a fast response speed of 99/117 mu s, 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.