Investigating laser induced phase engineering in MoS2 transistors

TL;DR

This study explores the effects of laser radiation on MoS2 transistors, aiming to induce phase transitions from metallic to semiconducting forms, but finds that laser treatment degrades device performance instead of restoring semiconducting properties.

Contribution

It demonstrates the impact of laser exposure on 1T/1T'-MoS2 transistors and highlights challenges in achieving in-situ phase transitions for device fabrication.

Findings

Laser exposure increases 2H-MoS2 Raman peaks.

Laser treatment degrades the transport channel.

Semiconducting properties are not fully restored after laser exposure.

Abstract

Phase engineering of MoS2 transistors has recently been demonstrated and has led to record low contact resistances. The phase patterning of MoS2 flakes with laser radiation has also been realized via spectroscopic methods, which invites the potential of controlling the metallic and semiconducting phases of MoS2 transistors by simple light exposure. Nevertheless, the fabrication and demonstration of laser patterned MoS2 devices starting from the metallic polymorph has not been demonstrated yet. Here, we study the effects of laser radiation on 1T/1T'-MoS2 transistors with the prospect of driving an in-situ phase transition to the 2H-polymorph through light exposure. We find that although the Raman peaks of 2H-MoS2 become more prominent and the ones from the 1T/1T' phase fade after the laser exposure, the semiconducting properties of the laser patterned devices are not fully restored and the laser treatment ultimately leads to degradation of the transport channel.