Open Access Nano Express

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

Chao Shen1, Gaoshan Huang1*, Yingchun Cheng2*, Ronggen Cao1, Fei Ding3, Udo Schwingenschlögl2 and Yongfeng Mei1*

Author Affiliations

1 Department of Materials Science, Fudan University, Shanghai, 200433, People's Republic of China

2 PSE Division, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia

3 IBM Research − Zürich, Säumerstrasse 4, Rüschlikon, CH-8803, Switzerland

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Nanoscale Research Letters 2012, 7:268  doi:10.1186/1556-276X-7-268

Published: 24 May 2012

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.

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

Keywords:
Graphene sheets; Plasma; Thinning; Functionalization; Raman spectroscopy; Density functional theory; Dirac cone splitting