Photogating Effect of Atomically Thin Graphene/MoS₂/MoTe₂ van der Waals Heterostructures

The development of short-wave infrared photodetectors based on various two-dimensional (2D) materials has recently attracted attention because of the ability of these devices to operate at room temperature. Although van der Waals heterostructures of 2D materials with type-II band alignment have significant potential for use in short-wave infrared photodetectors, there is a need to develop photodetectors with high photoresponsivity. In this study, we investigated the photogating of graphene using a monolayer-MoS2/monolayer-MoTe2 van der Waals heterostructure. By stacking MoS2/MoTe2 on graphene, we fabricated a broadband photodetector that exhibited a high photoresponsivity (>100 mA/W) and a low dark current (60 nA) over a wide wavelength range (488−1550 nm).