In-situ Raman study of laser-induced graphene oxidation

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’m patterning of graphene by an optical method. Evolution of the D/G-mode ratio in laser-irradiated single-layer graphene, as well as a representative Raman spectrum.