Bandgap Extraction and Device Analysis of Ionic Liquid Gated WSe<sub>2</sub> Schottky Barrier Transistors.

Prakash, Abhijith; Appenzeller, Joerg · ACS Nano · 2017

basic_science · Level V

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Abstract

Through the careful study of ionic liquid gated WSe<sub>2</sub> Schottky barrier field-effect transistors as a function of flake thickness-referred to in the following as body thickness, t<sub>body</sub>-critical insights into the electrical properties of WSe<sub>2</sub> are gained. One finding is that the inverse subthreshold slope shows a clear dependence on body thickness, i.e., an approximate square root dependent increase with t<sub>body</sub>, that provides evidence that injection into the WSe<sub>2</sub> channel is mediated by thermally assisted tunneling through the gate-controlled Schottky barriers at the source and drain. By employing our Schottky barrier model, a detailed experimental plot of the WSe<sub>2</sub> bandgap as a function of body thickness is obtained. We will discuss why the analysis employed here is critically dependent on the use of the above-mentioned ionic liquid gate and how device characteristics are analyzed in detail.