Effect of radical fluorination on mono- and bi-layer graphene in Ar/F2 plasma

Fluorinated graphene has the possibility to achieve unique properties and functions in graphene. We propose a highly controlled fluorination method utilizing fluorine radicals in Ar/F-2 plasma. To suppress ion bombardments and improve the reaction with fluorine radicals on graphene, the substrate was placed face down in the plasma chamber. Although monolayer graphene was more reactive than bilayer, fluorination of bilayer reached the level of I-D/I-G similar to 0.5 in Raman D peak intensity at 532 nm excitation. Annealing fluorinated samples proved reversibility of radical fluorination for both mono- and bi-layer graphenes. X-ray photoelectron spectroscopy showed the existence of carbon-fluorine bonding. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4760268]