Comparison of Ionic Liquid and Ion-Gel Top-Gate MoS₂ Field-Effect Transistors

Abstract

Polymer electrolytes and ionic liquids (ILs) have attracted significant interest in applications as gate dielectrics. In this study, we fabricated top-gated molybdenum disulfide (MoS 2 ) thin-film transistors using IL and ion-gel (IG) gate dielectrics. Room-temperature Raman spectra measurements indicated a dominant peak spectral emission at 358 cm −1 (𝐸 1 2𝑔 ) and 406.44 cm −1 (𝐴 1g ) associated with bilayer MoS 2 films. The fabricated thin-film field-effect transistors (FET) with IG gate dielectric exhibited band transport with a highest mobility of 0.5 cm 2 /V⋅s, and a poor 𝐼 ON /𝐼 OFF ratio of ~10. By contrast, the FET with IL gate dielectric exhibited a 3400 % improvement in terms of the mobility (17.9 cm 2 /V⋅s), and a 1000 % improvement of the 𝐼 ON /𝐼 OFF ratio (~100).