Self‐Powered Photodetector with High Performance Based on All‐2D NbSe 2 /MoSe 2 van der Waals Heterostructure

Abstract 2D materials provide an effective strategy for the construction of fast‐responsive and highly sensitive Schottky heterojunction devices. However, the strong Fermi pinning at the contact between bulk metallic electrodes and 2D semiconductor materials greatly hinders the wide application of such devices in optoelectronics. Herein, a self‐powered photodetector with high performance is fabricated based on an all‐2D van der Waals (vdWs) heterojunction composed of metallic 2H‐NbSe 2 and semiconducting MoSe 2 . Benefiting from the strong built‐in electric field, the device exhibits a high rectification ratio of 2.1 × 10 3 . Furthermore, the photovoltaic effect can be observed in a broad spectrum ranging from 405 to 980 nm without external voltage, where a maximum responsivity of 64.92 A W −1 , a maximum specific detectivity of 2.39 × 10 14 Jones, and a large on–off current ratio >10 5 are obtained at 650 nm. Simultaneously, the efficient charge separation at the high‐quality heterointerface of NbSe 2 /MoSe 2 results in a fast response/recovery time of 180/80 µs. This work demonstrates the promising potential of the 2D metallic NbSe 2 as an electrode forming a Schottky heterojunction to realize a high‐performance broadband photodetector for near‐infrared communication.