Removal of Organic Contamination from Graphene with a Controllable Mass-Selected Argon Gas Cluster Ion Beam

Abstract

Since the discovery of graphene, organic surface contamination has posed difficulties both for accurate characterization of the material’s intrinsic properties and for development of graphene devices. In this study, we investigate the use of a mass-selected argon gas cluster ion beam for removing organic contaminants, such as residual poly(methyl methacrylate) (PMMA), from single-layer graphene. The influence of cluster ion size, energy, and ion dose has been investigated to identify the important factors for minimizing damage to the graphene layer during the cleaning process. Raman spectroscopy was used to analyze the variation in the D-peak and G-peak intensity ratio, an indicator of damage to the graphene lattice, as a function of ion beam dose and kinetic energy per atom (E/n) in the cluster ions. Using a mass-selected 5 keV Ar5000 beam with a dose of 5.0 ions/nm2, we were able to demonstrate removal of polymer residue and other carbonaceous material from single-layer chemical vapor deposition (CVD)-g...