(color online) (a) Schematic illustration (top left) of the photodetector based on graphene/MoS₂heterostructure, where the channel is formed in between the comb-shaped source and drain metal electrodes (top right). Photoresponsivity (bottom left) and photogain (bottom right) for the graphene/MoS₂ photodetectors.^[74] (b) I–V characteristics of the graphene–MoS₂–graphene heterostructures-based device under laser illumination. Schematic illustration of the side view of the device (inset).^[75] (c) Schematic diagram of a van derWaals-stacked MoS₂/WSe₂ heterojunction device with lateral metal contacts (top). Measured and simulated photocurrent at V_ds = 0 V as a function of gate voltages (bottom). Photocurrent map of the device (inset).^[76] (d) Cross-section schematic of MoS₂–graphene–WSe₂ heterostructure based photodetector (top). Photoresponsivity R (left) and specific detectivity D* (right) of a typical device for wavelengths range from 400 to 2400 nm measured in ambient air (bottom). Optical image of the device (inset).^[77]