title: 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.
authors.affiliation: Department of Materials Science, Fudan University, Shanghai, 200433, People's Republic of China. gshuang@fudan.edu.cn.
authors.forename: Chao
authors.initials: C
authors.lastname: Shen
authors.forename: Gaoshan
authors.initials: G
authors.lastname: Huang
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Cheng
authors.forename: Ronggen
authors.initials: R
authors.lastname: Cao
authors.forename: Fei
authors.initials: F
authors.lastname: Ding
authors.forename: Udo
authors.initials: U
authors.lastname: Schwingenschlögl
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Mei