CMOS-compatible Au doping boosts the hole carrier transport in the CVD-grown 2-inch monolayer WSe2 films for p-type transistors

Abstract

Although the wafer-scale growth of n-type MoS₂ and its NMOS devices already show great potential for application in future electronics with ultra-short channels, the development of a p-type two-dimensional semiconductor is still in an early stage. The CMOS-compatible fabrication and stable p-type transistor development are significant challenges that hinder the development of CMOS-based integrated circuits with ultra-low power. In this study, we realized the 2-inch wafer-scale growth of a monolayer WSe₂ film and propose a strategy to achieve uniform doping by depositing 0.5 nm Au on the surface of WSe₂ via electron beam evaporation, followed by annealing. The results show that after annealing at 400 °C, the deposited thin Au layer aggregated to form Au nanoparticles, which were uniformly distributed on the surface of WSe₂ films with a good interface, as proven by atomic-resolution cross-section analysis. Moreover, the investigation of the top-gate transistor arrays verified that the WSe₂-Au sample annealed at 400 °C exhibited excellent doping stability and uniformity: the mobility increased by 46 times, the ON/OFF ratio improved by two orders of magnitude, and the subthreshold swing significantly reduced from 2.35 V dec⁻¹ to 0.77 V dec⁻¹. This uniform doping method shows great potential for the development of wafer-scale 2D materials in the field of integrated circuits.