Carrier-type modulation of tungsten diselenide (WSe2) field-effect transistors (FETs) via benzyl viologen (BV) doping.

[Display omitted] • Mechanically exfoliated multilayer WSe 2 FETs exhibit carrier-type transition. • Transition occurs from hole-dominant to electron-dominant upon BV doping. • BV-doped devices can undergo complete recovery by toluene immersion. • Electrical properties of WSe 2 devices secured via PMMA encapsulation of surface. With the advancement of technology based on low-dimensional materials, numerous attempts have been made to tune the semiconducting behavior of field-effect transistors to broaden their potential applications in various fields of electronics. Herein, a stable and site-selective method for the surface doping of tungsten diselenide devices is presented. Experimental results suggested that benzyl viologen doping induced a carrier-type transition effect on the device, and the electrical properties were successfully recovered after immersion in toluene solution. The recovered device was exposed to low-vacuum conditions for 10 d; no additional defects were observed on the interface. [ABSTRACT FROM AUTHOR]