High-gain complementary metal-oxide-semiconductor inverter based on multi-layer WSe₂ field effect transistors without doping

A high-gain complementary metal-oxide-semiconductor (CMOS) logic inverter was implemented by fabricating p - and n -type field effect transistors (FETs) based on multi-layer WSe₂ on the same wafer. Au as a high work-function metal is contacted to WSe₂ for the source/drain of the p -type FET. The n -type FET has an Al electrode contacted to WSe₂ for the source/drain. Both FETs were designed to have similar on-current densities (>10⁻⁷ A μ m⁻¹) and high on/off current ratios (>10⁶). The inverter shows excellent switching characteristics including relatively high voltage gains (>25) and high noise margins (>0.9) in the range of supply voltage from 2 V to 8 V. This work has a great significance in the realization of a CMOS logic gate based on WSe₂ without an additional doping scheme. (paper)