Figure 6.

a) Optical image of bilayered MoTe₂‐based field‐effect transistors. b) The linear curves of I _ds–V _ds applied by different bias. The inset shows a subthreshold swing SS ≈140 mV, when I _ds as a function of V _bg in a limited scale. c) Conductivity (left axis) and mobility (right axis) as a function of V _bg varied from 40 to −40 V. Reproduced with permission.167 Copyright 2014, American Chemical Society. d) The back‐gate transfer curves of MoT_e2‐based phototransistors under the P_up state (red curve) and P_down state (dark curve) of top gate fixing V _ds at 1 V. Inset: Image of few‐layer MoTe₂‐based FET with a ferroelectric polymer top gate. e) The output characteristics with fresh state (ferroelectric layer without polarization), P_up state, and P_down state. Reproduced with permission.75 Copyright 2016, Royal Society of Chemistry. f) The transfer curve of a ReS₂ transistor at a fixed V _ds value of 1.0 V. Inset: AFM image of ReS₂ device. Reproduced with permission.83 g) Transfer curves of monolayer (red) and trilayer (blue) ReS₂ FET devices, when V _ds is fixed at 100 mV. h) Transfer curves of anisotropic ReS₂ FETs along A and B direction of a five‐layer flake (with an inner angle of 60° or 120°. Top inset shows optical image of the devices and the inset in the bottom performs the four‐probe resistance under V _bg varying between 0 and 60 V. i) The calculated (red dots) and experimental (blue dots) mobility of monolayer ReS₂ is plotted in the same graph, and the lowest mobility direction was set to be the 0° (or 180°) reference. Inset: The optical image of the device. Reproduced with permission.67 Copyright 2015, the authors, published under CC‐BY‐4.0 license.