Controlled modification of mono- and bilayer graphene in O, H and CF plasmas

A. Felten, J.-J. Pireaux, A. Eckmann, C. Casiraghi, R. Krupke

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Abstract

In this work, covalent modification of mono- and bilayer graphene is achieved using tetrafluoromethane (CF), oxygen and hydrogen RF plasma. Controlled modification of graphene is usually difficult to achieve, in particular with oxygen plasma, which is rather aggressive and usually leads to etching of graphene. Here we use x-ray photoelectron spectroscopy and Raman spectroscopy to show that mild plasma conditions and fine tuning of the number of functional groups can be obtained in all plasmas by varying parameters such as exposure time and sample position inside the chamber. We found that even for the usual harsh oxygen treatment the defect density could be lowered, down to one defect for 3.5 × 10 carbon atoms. Furthermore, we show that CF plasma leads to functionalization without etching and that graphene becomes an insulator at saturation coverage. In addition, the reactivity of mono- and bilayer graphene was studied revealing faster modification of monolayer in oxygen and CF plasma, in agreement with previous works. In contrast, similar modification rates were observed for both mono- and bilayer during hydrogenation. We attribute this discrepancy to the presence of more energetic species in the hydrogen plasma such as positive ions that could play a role in the functionalization process.
Original languageEnglish
Article number355705
JournalNanotechnology
Volume24
Issue number35
DOIs
Publication statusPublished - 6 Aug 2013

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Graphene
Monolayers
Plasmas
Oxygen
Hydrogen
Etching
Defect density
Photoelectron spectroscopy
Functional groups
Hydrogenation
Raman spectroscopy
Carbon
Tuning
Positive ions
X rays
Atoms
Defects

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Controlled modification of mono- and bilayer graphene in O, H and CF plasmas. / Felten, A.; Pireaux, J.-J.; Eckmann, A.; Casiraghi, C.; Krupke, R.

In: Nanotechnology, Vol. 24, No. 35, 355705, 06.08.2013.

Research output: Contribution to journalArticle

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