A Strategic Approach for Enhanced p‐Type Doping of WSe2 p‐MOSFETs Using an Atomic Oxidation Process

Abstract

Doping allows precise tuning of the electronic properties in 2D materials, optimizing their performance for applications such as complementary metal‐oxide‐semiconductor (CMOS) technology. However, developing reliable p‐type 2D semiconductors remains challenging due to intrinsic defects or unintentional n‐type doping. This study presents robust p‐type monolayer WSe2 field‐effect transistors (FETs) using phase‐engineered WSe2/WSeyOx building blocks created via an atomic oxidation process (AOP). The findings reveal that when bilayer WSe2 is exposed to AOP, the top layer undergoes self‐limited oxidation to WSeyOx with no detectable oxidation of the bottom layer. This result is confirmed by Raman spectroscopy, X‐ray photoelectron spectroscopy, and Kelvin probe force microscopy. This process has further been used to demonstrate a well‐controlled and fully encapsulated WSeyOx/WSe2/WSeyOx heterostructure, ensuring symmetrical protection and stability of the WSe2 channel region. The surface charge transfer doping using WSeyOx provides the capability to selectively modulate the carrier concentration in a WSe2 without altering the intrinsic properties of the channel. This non‐destructive method simplifies the fabrication of p‐type 2D FETs with monolithic, phase‐engineered heterostructures, facilitating seamless integration into next‐generation device architectures.