High-current p-type transistors from precursor-engineered synthetic monolayer WSe₂

Monolayer tungsten diselenide (WSe₂) is a leading candidate for nanoscale complementary logic. However, high defect densities introduced during thin-film growth and device fabrication have limited p-type transistor performance. Here, we report a combined strategy of precursor-engineered chemical vapor deposition and damage-minimizing fabrication to overcome this limitation. By converting tungsten trioxide and residual oxyselenides into reactive suboxides before growth, and precisely regulating selenium delivery during deposition, we synthesize uniform, centimeter-scale monolayer WSe₂ films with charged defect densities as low as 5 × 10⁹ cm⁻². Transistors fabricated from these films achieve record p-type on-state current up to $888 μ$A·μm⁻¹ at VDS=-1 V, matching leading n-type devices. This leap in material quality closes the p-type performance gap without exotic doping or contact materials, marking a critical step towards complementary two-dimensional semiconductor circuits.