# Oxide-mediated self-limiting recovery of field effect mobility in plasma-treated MoS$_2$

## TL;DR

This study demonstrates that oxygen plasma treatment can be used to precisely tune and enhance the electrical properties of MoS₂ by forming a beneficial 2D MoO₃ phase, challenging previous assumptions about plasma damage.

## Contribution

The paper reveals that controlled oxygen plasma treatment induces a 2D MoO₃ phase in MoS₂, leading to improved mobility and conductivity, providing new insights into 2D material modification.

## Key findings

- Oxygen plasma treatment enhances MoS₂ electrical performance.
- Formation of 2D MoO₃ phase improves conductivity.
- Theoretical models confirm the beneficial role of MoO₃.

## Abstract

Precise tunability of electronic properties of 2D nanomaterials is a key goal of current research in this field of materials science. Chemical modification of layered transition metal dichalcogenides leads to the creation of heterostructures of low-dimensional variants of these materials. In particular, the effect of oxygen-containing plasma treatment on molybdenum disulfide (MoS$_2$) has long been thought to be detrimental to the electrical performance of the material. Here we show that the mobility and conductivity of MoS$_2$ can be precisely controlled and improved by systematic exposure to oxygen:argon plasma, and characterise the material utilising advanced spectroscopy and microscopy. Through complementary theoretical modelling which confirms conductivity enhancement, we uncover the role of a two-dimensional phase of molybdenum trioxide (2D-MoO$_3$) in improving the electronic behaviour of the material. Deduction of the beneficial role of MoO$_3$ will serve to open the field to new approaches with regard to the tunability of 2D semiconductors by their low-dimensional oxides in nano-modified heterostructures.