In-situ Raman study of laser-induced graphene oxidation

TL;DR

This study uses in-situ Raman spectroscopy to analyze laser-induced oxidation in single-layer graphene, revealing a two-stage process involving strain and doping, and demonstrating potential for optical patterning.

Contribution

It provides new insights into the oxidation mechanism of graphene under laser irradiation and shows how to control this process for precise patterning.

Findings

Oxidation occurs in two stages: strain and doping.

Steady decrease of D mode at long irradiation times.

Optical patterning of graphene is feasible.

Abstract

We present in-situ Raman measurements of laser-induced oxidation in exfoliated single-layer graphene. By using high-power laser irradiation, we can selectively and in a controlled way initiate the oxidation process and investigate its evolution over time. Our results show that the laser-induced oxidation process is divided into two separate stages, namely tensile strain due to heating and subsequent $p$-type doping due to oxygen binding. We discuss the temporal evolution of the $D/G$-mode ratio during oxidation and explain the unexpected steady decrease of the defect-induced $D$ mode at long irradiation times. Our results provide a deeper understanding of the oxidation process in single-layer graphene and demonstrate the possibility of sub-$\mu$m patterning of graphene by an optical method.