Precise control of defects in graphene using oxygen plasma

The authors report on a facile method for introducing defects in graphene in a controlled manner. Samples were mounted face down between supports, and exposed to oxygen plasma in a reactive ion etching (RIE) system. Defect density and the rate of defect formation in graphene were analyzed according to the oxygen flow rates and power conditions, using Raman spectroscopy. The mechanism of defect formation was systematically investigated via both experiment and density functional theory (DFT) calculation. Based on our DFT results, sp(3) oxygen in the epoxide form would most likely be induced in pristine graphene after exposure to the oxygen plasma. Defect engineering through the fine tuning of the graphene disorder using a conventional RIE system has great potential for use in various graphene-based applications. (C) 2015 American Vacuum Society.