Double-Side-Doped 2D TMD FET Channel

Control over doping plays a critical role in advancing field-effect transistors (FETs). However, such on-demand doping remains an outstanding challenge for layered two-dimensional (2D) materials. Here, we demonstrate robust mono- and bilayer WSe2 FETs with highly controllable and stable doping by integrating oxidation-induced WOx charge-transfer dopants on the top and bottom surfaces of WSe2 on demand. Upon oxidation of WSe2, we observe well-controlled layer-number-dependent doping of WSe2, as evidenced by the red shift of Raman and photoluminescence peaks. We further observe highly controllable and stable p-type doping in mono- and bilayer WSe2 FETs as the bottom and top surfaces are sequentially doped by WOx and subsequently capped by insulating SiO2 and hexagonal boron nitride (hBN). Our work paves avenues for highly stable and on-demand doping of 2D semiconductors, enabling seamless integration of 2D semiconductors into next-generation device architectures.