Photoinduced doping in monolayer WSe 2 transistors

Modulation of carrier type and concentration is of fundamental importance to 2D electronic and optoelectronic devices. We report photoinduced doping of monolayer WSe2 transistors through the combination of laser illumination and the gate bias, which is further confirmed by photoluminescence measurement. The scheme can be completed within hundreds of milliseconds and achieve reversible doping modulation. Optical property at low temperature, transient response, and retention characteristics of FETs suggest that the observed photoinduced doping can be mainly attributed to trap sites at the imperfect WSe2/SiO2 interfaces and the exfoliation-induced interlayer deformation.