Thinning and functionalization of few-layer graphene sheets by CF4 plasma treatment

Abstract

Structural changes of few-layer graphene sheets induced by CF₄ plasma treatment are studied by optical microscopy and Raman spectroscopy, together with theoretical simulation. Experimental results suggest a thickness reduction of few-layer graphene sheets subjected to prolonged CF₄ plasma treatment while plasma treatment with short time only leads to fluorine functionalization on the surface layer by formation of covalent bonds. Raman spectra reveal an increase in disorder by physical disruption of the graphene lattice as well as functionalization during the plasma treatment. The F/CF₃ adsorption and the lattice distortion produced are proved by theoretical simulation using density functional theory, which also predicts p-type doping and Dirac cone splitting in CF₄ plasma-treated graphene sheets that may have potential in future graphene-based micro/nanodevices.

PACS

81.05.ue; 73.22.Pr; 52.40.Hf.