Figure 7.

a) The curves of V _ds–I _ds fixed at V _g = 0 V under a different power of 685 nm laser. Inset: The schematic and two optical images of MoTe₂ few‐layer FET. b) Photoresponse occurred in MoTe₂ device at V _ds = 5 V, V _g = 0 V under a laser of 178 Hz and 20 µW. Zoomed region shows a rise time and a fall time. Reproduced with permission.22 c) Output characteristics of the curve of the ReS₂ back‐gate device under different incident laser powers. Inset: The schematic structure of ReS₂ photodetector. d) Photoresponse occurred with time‐dependent I _ds of the device under an intermittent laser illumination. Inset: Enlarged image of the photoresponse peak over a small range. Reproduced with permission.115 e) The characteristic I–V curves were illuminated by light of the single ReS₂ device. Inset: The schematic image of the device. f) Photoresponse occurred in ReS₂ polycrystalline bilayer film with photocurrent under 500 nm incident light. Reproduced with permission.84 g) The schematic of the few‐layer ReS₂ phototransistors. h) Linear transfer curves in the dark state and under illumination. Inset: Photoresponsivity as a function of V _bg at the top and optical microscopy image and AFM image of the same device at the bottom. i) Photoswitching behaviors with high photoresponsivity under various V _ds. j) Weak signal detection in a five‐layer ReS₂ phototransistor, fixing V _bg at −50 V and V _ds at 2.0 V. Reproduced with permission.83