Laser-assisted Oxidation of Multi-layer Tungsten Diselenide Nanosheets

TL;DR

This study investigates laser-induced oxidation of multi-layer tungsten diselenide nanosheets, revealing increased conductivity and potential applications in patterning and electrical contacts for transition metal dichalcogenides.

Contribution

It introduces a laser-assisted oxidation method for WSe2 nanosheets and characterizes the resulting conductive oxide structures using advanced microscopy.

Findings

Oxidized WSe2 shows ~100 S/m conductivity.

Laser oxidation forms sub-stoichiometric WO3-x polycrystals.

Potential for patterning conductive features on 2D materials.

Abstract

We report the structural and electrical characterization of tungsten oxides formed by illuminating multi-layer tungsten diselenide (WSe2) nanosheets with an intense laser beam in the ambient environment. A noninvasive microwave impedance microscope (MIM) was used to perform electrical imaging of the samples. The local conductivity ~100 S/m of the oxidized product, measured by the MIM and conventional transport experiments, is much higher than that of the pristine WSe2, suggesting the formation of sub-stoichiometric WO3-x polycrystals with n-type carriers. With further efforts to improve the conductivity of the oxides, the laser-assisted oxidation process may be useful for patterning conductive features on WSe2 or forming electrical contacts to various transition metal dichalcogenides.