Wafer-scale CVD Monolayer WSe2 p-FETs with Record-high 727 μA/μm Ion and 490 μS/ μm gmax via Hybrid Charge Transfer and Molecular Doping

This study introduces a novel hybrid p-doping strategy, integrating tungsten oxide (WO x ) charge transfer and nitric oxide (NO) molecular doping with wafer-scale CVD grown monolayer tungsten diselenide (1L-WSe 2 ). This hybrid doping approach has enabled a record-high on-current I ON of 727 μA/μm at a V DS of -1.5 V and a record-high transconductance (g m ) of 490 μS/μm, while maintaining an excellent on-off current ratio of ~ 9 orders of magnitude in wafer-scale CVD 1L-WSe 2 p-FETs. We fabricated field-effect transistors in which 1L-WSe 2 is encapsulated by its native oxide WO x interfacial layer (IL). Analogous to the role of SiO 2 IL in Si CMOS, the native oxide WO x IL can effectively preserve intrinsic channel properties and allow for threshold voltage (V TH ) tuning without compromising the on-off ratio. Furthermore, nitric oxide (NO) molecular doping was employed to further shift V TH for p-type doping. Unlike most reported doping techniques, NO doping improves the device on-current as well as the subthreshold swing (SS), without sacrificing the on-off ratio. This pioneering hybrid doping scheme could lay the foundation for the development of high-performance PMOS devices based on 2D WSe 2 .