Improving electron mobility in MoS2 field-effect transistors by optimizing the interface contact and enhancing the channel conductance through local structural phase transition

Abstract

The microscale structural phase transition in TMDs from 2H to 1T or 1T′ phases offers a distinct approach for modulating the electronic properties of these materials. Although phase engineering for contacts has been partially investigated, the effect of embedding 1T domains in the semiconductor channel on electronic transport has rarely been studied. Here, we investigate the electronic performance of few-layer MoS₂ FETs with a local 1T structural phase transition. Through a mild oxygen plasma treatment, we successfully incorporated the 1T phase into the 2H-MoS₂ host and observed a significant improvement in the electron mobility of the MoS₂ FETs. On the contact side, the local 1T domain serves as a conductive bridge connecting the Au electrode and MoS₂ channel, which substantially improves the carrier-injection efficiency. On the channel side, 1T embedded 2H-MoS₂ can effectively tailor the electronic structure of the MoS₂ channel, significantly increasing channel conductivity. Compared with that before the oxygen plasma treatment, the MoS₂ FET demonstrated a higher maximum electron mobility of about two orders of magnitude (up to 237 cm² V⁻¹ s⁻¹). This study could further promote the development of advanced two-dimensional electronic devices with improved performances.