Field-effect transistors made from solution-grown two-dimensional tellurene

TL;DR

This paper presents a solution-based method to produce large-area, high-quality 2D tellurene with tunable thickness and demonstrates its application in air-stable field-effect transistors with high performance metrics.

Contribution

The study introduces a substrate-free solution process for fabricating large-area tellurene with tunable thickness and demonstrates high-performance, air-stable FETs based on this material.

Findings

Crystals with up to 100 um lateral size and tunable thickness.

FETs with on/off ratios of 10^6 and mobility around 700 cm^2/Vs.

Transistors with 1 A/mm current density by scaling channel length.

Abstract

The reliable production of two-dimensional crystals is essential for the development of new technologies based on 2D materials. However, current synthesis methods suffer from a variety of drawbacks, including limitations in crystal size and stability. Here, we report the fabrication of large-area, high-quality 2D tellurium (tellurene) using a substrate-free solution process. Our approach can create crystals with a process-tunable thickness, from monolayer to tens of nanometres, and with lateral sizes of up to 100 um. The chiral-chain van der Waals structure of tellurene gives rise to strong in-plane anisotropic properties and large thickness dependent shifts in Raman vibrational modes, which is not observed in other 2D layered materials. We also fabricate tellurene field-effect transistors, which exhibit air-stable performance at room temperature for over two months, on off ratios on the order of 106 and field-effect mobilities of around 700 cm2 per Vs. Furthermore, by scaling down the channel length and integrating with high-k dielectrics, transistors with a significant on-state current density of 1 A mm-1 are demonstrated.