Fig. 2

Phototransistor with tunable sensitivity. a Schematic of the phototransistor, consisting of a MoS₂ FET integrated with a photodiode. h-BN serves as both the dielectric and protective layer, while graphite is used as the contact and gate electrode. b Cross-section HRTEM image of the h-BN/MoS₂/h-BN heterojunction and elemental maps of S, Mo, N, O for the heterojunction. c Cross-section HRTEM image of the Gr/ O-plasma-treated MoS₂/h-BN heterojunction and elemental maps of S, Mo, N, C, O for the heterojunction. d, e O, S, and Mo atomic ratio for pristine and O-plasma-treated MoS₂ samples. f Band structure of the device in the dark. g Band structure of the device under illumination. h Device symbol showing a diode inserted in the gate stack of the FET. i Transfer characteristics (I_DS−V_GS) of the tunable-sensitivity phototransistor in dark and under varying 516-nm light intensities at V_DS = 0.1 V