Proton-Conductor-Gated MoS₂ Transistors with Room Temperature Electron Mobility of >100 cm² V^–1 s^–1

Room temperature electron mobility of >100 cm2 V–1 s–1 is achieved for a few-layer MoS2 transistor by use of a polyanionic proton conductor as the top-gate dielectric of the device. The use of a proton conductor that inherently exhibits a cationic transport number close to 1 yields unipolar electron transport in the MoS2 channel. The high mobility value is attributed to the effective formation of an electric double layer by the proton conductor, which facilitates electron injection into the MoS2 channel, and to the effective screening of the charged impurities in the vicinity of the device channel. Through careful temperature-dependent transistor and capacitor measurements, we also confirm quenching of the phonon modes in the proton-conductor-gated MoS2 channel, which should also contribute to the achieved high mobility. These devices are then used to assemble a simple resistive-load inverter logic circuit, which can be switched at high frequencies above 1 kHz.