A WSe2 vertical field emission transistor

TL;DR

This paper demonstrates the first gate-controlled field emission from a WSe2 monolayer transistor, showing stable electron emission modulated by gate voltage, paving the way for vacuum electronic devices.

Contribution

It introduces the first WSe2 monolayer vertical field emission transistor with gate-tunable electron emission capabilities.

Findings

Electron emission occurs at ~100 V/μm electric field.

Emission current is modulated by back-gate voltage.

Device exhibits good time stability.

Abstract

We report the first observation of gate-controlled field emission current from a tungsten diselenide (WSe2) monolayer, synthesized by chemical-vapour deposition on SiO2/Si substrate. Ni contacted WSe2 monolayer back-gated transistors, under high vacuum, exhibit n-type conduction and drain-bias dependent transfer characteristics, which are attributed to oxygen/water desorption and drain induced Schottky barrier lowering, respectively. The gate-tuned n-type conduction enables field emission, i.e. the extraction of electrons by quantum tunnelling, even from the flat part of the WSe2 monolayers. Electron emission occurs under an electric field ~100 V {\mu}m^(-1) and exhibit good time stability. Remarkably, the field emission current can be modulated by the back-gate voltage. The first field-emission vertical transistor based on WSe2 monolayer is thus demonstrated and can pave the way to further optimize new WSe2 based devices for use in vacuum electronics.