Top-gate field-effect transistor based on monolayer WS₂ with an ion-gel gate dielectric

Abstract

A top-gate field-effect transistor (FET), based on monolayer (ML) tungsten disulfide (WS2), and with an ion-gel dielectric was developed. The high electrical contact resistance of the Schottky contacts at the n-type transition metal dichalcogenides/metal electrode interfaces often adversely affects the device performance. We report the contact resistance and Schottky barrier height of an FET with Au electrodes. The FET is based on ML WS2 that was synthesised using chemical vapour deposition and was assessed using the transfer-length method and low-temperature measurements. Raman and photoluminescence spectra were recorded to determine the optical properties of the WS2 layers. The ML WS2 FET with an ion-gel top gate dielectric exhibits n-type behaviour, with a mobility, on/off ratio of 1.97 cm2/V·s, 1.51×105, respectively.

Sublimation-based wafer-scale monolayer WS2 formation via self-limited thinning of few-layer WS2

“…Our values compare rather favorably to those reported in the literature ( μ eff = 0.16–1.97 cm 2 V −1 s −1 ) for the exfoliated single crystalline monolayer WS 2 FETs fabricated with similar source and drain metal contacts, 9,42,43 implying the good quality of our monolayer WS 2 film. It must be pointed out that, while the intrinsic mobility is a material-related parameter that is determined by intrinsic material properties such as crystallinity, crystal-defects/impurities, and grain sizes etc.…”

Ionic dielectrics for fully printed carbon nanotube transistors: impact of composition and induced stresses

“…Simply put, ionic dielectrics are composed of ions in a material that supports ionic conduction. Many compositional variations of ionic dielectrics have been successfully demonstrated in TFTs with semiconducting channels of organic semiconductors, [25][26][27] 2D materials, [28][29][30] or CNTs. 31,32 Each ionic dielectric has a thickness-independent capacitance due to EDL formation at the dielectric/channel and dielectric/electrode interfaces.…”