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 WO_x 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 WSe_2, 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 WO_x 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.