Phosphorus-ion implantation in two-dimensional WSe2 for hole doping

As silicon-based devices near their scaling limits, transition-metal dichalcogenides (TMDCs) such as tungsten diselenide (WSe2) have emerged as promising alternatives. However, the lack of a wafer-scale, industry-compatible doping technique has hindered their integration into standard semiconductor processes. In this study, we demonstrate a complementary metal-oxide-semiconductor (CMOS)-compatible p-type doping strategy for WSe2 involving phosphorus-ion implantation followed by rapid thermal annealing. Through Stopping and Range of Ions in Materials simulations of WSe2 encapsulated with SiO2 (150 nm), the implantation energy (150 keV) of a phosphorus ion with a dose of 5 × 1013 ions/cm2 was selected to localize the dopants near the surface of WSe2. The postannealing optimized at 900 °C for 3 min in Ar ambient after phosphorus-ion implantation resulted in a 124 mV surface-potential reduction in the WSe2 layer, as revealed by Kelvin probe force microscopy. A reduction in sheet resistance from 2 × 106 to 117 kΩ/sq. and a reduction in contact resistance from 2.13 × 107 to 194 kΩ μm were observed compared with pristine WSe2, indicating the activation of the dopants and restoration of the lattice structure. A vertical p–n diode fabricated with phosphorus-doped WSe2 and n-type MoS2 exhibited near-ideal rectifying behavior, with an ideality factor of 1.1 and a photocurrent of 1.8 nA under 530 nm illumination. This study provides a scalable and CMOS-compatible doping method for TMDCs, paving the way for their integration into advanced nanoelectronic devices.