Novel Transfer Behaviors in 2D MoS₂/WSe₂ Heterotransistor and Its Applications in Visible-Near Infrared Photodetection

This paper demonstrates the fabrication and operation of a vertically integrated phototransistor based on single-layer MoS₂/multilayer WSe₂ van der Waals heterojunction. Under the gate modulation effects, the device which combines advantages of their constituents displays a novel feature in the transfer characteristics where a current peak appears at small gate voltage bias and exhibits excellent optical broadband photodetecting properties. Upon visible light illumination (660 nm), the photodetection capabilities reach the optimal values simultaneously with the photoresponsivity of 17.8 A W⁻¹, photosensivity of 140, and the response speed of <80 ms. The device also shows good photoresponse under near-infrared light illumination (850 nm) and the obvious dependence on the gate voltage which plays a switching role for near infrared light photodetection. This 2D heterostructured broadband photodetector may provide an available device structure for an essential sensing component in the future wearable electronics applications.