Area-Selective UV Laser-Assisted Oxidation for Efficient Hole Injection in WSe ₂ FETs and Its Application to Multifunctional Logic Operations

Among two-dimensional (2D) semiconductors, WSe 2 is a promising channel material for next-generation low-power, high-density electronics; however, high contact resistance at the metal/WSe 2 interface remains a critical bottleneck in achieving optimal p -type channel performances. Herein, a 325-nm ultraviolet laser-assisted localized oxidation process is proposed to form sub-stoichiometric WO X near the metal contact to modulate contact properties. Lateral force microscopy is utilized to verify the presence of WO X domains through a distinct friction contrast and statistical roughness evolution, showing excellent agreement with high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy measurement. WO X induces localized p -type doping, reduces the effective Schottky barrier height, and lowers contact resistance by nearly four orders of magnitude without degrading channel crystallinity. The devices exhibit an on/off ratio of 10 7 and a subthreshold swing of 135 mV/dec. Selective WO X formation ensures efficient hole injection, whereas intrinsic n -type transport is maintained under global back-gate control, allowing for a polarity transition and five reconfigurable logic operations (OR, AND, NOR, NAND, and XNOR) in a single-transistor configuration. This laser-based strategy provides spatially selective, channel-preserving contact modulation with minimal thermal budget and establishes a scalable platform for advanced 2D logic electronics.