Tunable Polarity Behavior and High-Performance Photosensitive Characteristics in Schottky-Barrier Field-Effect Transistors Based on Multilayer WS2

Schottky-barrier field-effect transistors (SBFETs) based on multilayer WS 2 with Au as drain/source contacts are fabricated in this paper. Interestingly, the novel polarity behavior of the WS 2 SBFETs can be modulated by drain bias, ranging from p-type to ambipolar and finally to n-type conductivity, due to the transition of band structures and Schottky-barrier heights under different drain and gate biases. The electron mobility and the on/off ratio of electron current can reach as high as 23.4 cm 2 /(V s) and 8.5 × 10 7, respectively. Moreover, the WS 2 SBFET possesses high-performance photosensitive characteristics with response time of 40 ms, photoresponsivity of 12.4 A/W, external quantum efficiency of 2420%, and photodetectivity as high as 9.28 × 10 11 cm Hz 1/2 /W. In conclusion, the excellent performance of the WS 2 SBFETs may pave the way for next-generation electronic and photoelectronic devices.