# Photoresponsivity enhancement in monolayer MoS$_2$ by rapid O$_2$:Ar plasma treatment

## TL;DR

This study demonstrates that rapid O₂:Ar plasma treatment significantly enhances the photoresponsivity and electrical performance of monolayer MoS₂, offering a fast method to improve 2D material-based optoelectronic devices.

## Contribution

It introduces a plasma treatment method that increases photoresponsivity and mobility in monolayer MoS₂ by inducing surface MoOₓ formation, which was characterized by TEM, Raman, and PL.

## Key findings

- Up to ten-fold increase in photoresponsivity.
- Enhanced carrier mobility after plasma treatment.
- Surface oxidation to MoOₓ improves photocurrent generation.

## Abstract

We report up to ten-fold enhancement of the photoresponsivity of monolayer MoS$_2$ by treatment with O$_2$:Ar (1:3) plasma. We characterize the surface of plasma-exposed MoS$_2$ by TEM, Raman and PL mapping and discuss the role of MoO$_x$ in improving the photocurrent generation in our devices. At the highest tested laser power of 0.1 mW, we find ten-fold enhancements to both the output current and carrier field-effect mobility under the illumination wavelength of 488 nm. We suggest that the improvement of electrical performance is due to the surface presence of MoO$_x$ resulting from the chemical conversion of MoS$_2$ by the oxygen-containing plasma. Our results highlight the beneficial role of plasma treatment as a fast and convenient way of improving the properties of synthetic 2D MoS$_2$ devices for future consideration in optoelectronics research.