Realizing Ultrafast Respond Speed and High Detectivity for Gate-Modulated Self-Powered Photodetector with NbSe₂/MoS₂ van der Waals Heterostructure

2D materials offer an effective strategy for constructing self-powered Schottky junction devices with rapid response and high sensitivity. However, a single type of energy band coupling at the interface hinders the widespread applications of the photodetectors, while the changes of coupling types also face great challenges. Modulating the Fermi level and energy bands by gate voltage has emerged as a promising approach. In this study, a gate-modulated self-powered photodetector is fabricated based on a 2D van der Waals (vdWs) heterojunction composed of metallic NbSe₂ and semiconducting MoS₂. Due to its NbSe₂/MoS₂ vdWs heterostructure, the device exhibits a maximum responsivity of 455.3 mA/W, an excellent detectivity of 1.9 × 10¹² Jones, an ultrafast rise/decay time of 17/18 μs, and a broad spectral sensitivity under the irradiation ranging from 405 to 980 nm at zero bias. Furthermore, the corresponding responsivity and detectivity at a gate voltage of 40 V are around 7 times greater than those at -40 V. This work demonstrates the significant potential of 2D metallic NbSe₂ integrated into vdWs heterostructure to design a high-performance broadband photodetector for near-infrared communication.