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A. C. Ferrari1, J. C. Meyer2, V. Scardaci1, C. Casiraghi1, M. Lazzeri3, F.
Mauri3, S. Piscanec1, D. Jiang4, K. S. Novoselov4, A. K. Geim4
1-Cambridge University, Engineering Department, Cambridge CB3 0FA, UK 2-Max Planck Institute for Solid State Research, Stuttgart 70569, Germany 3-Institut de Mineralogie et de Physique des Milieux Condenses, Paris cedex 05, France 4-Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK We present the Raman spectrum of an isolated graphene layer and of n graphene layers having the same stacking as graphite, with n=2 to 10 [1]. These are supported by the identification of free-standing single and bi-layers by transmission electron microscopy and electron diffraction. We show that graphene\x{2019}s electronic structure is uniquely captured in its Raman spectrum and reflected in the shape, position and intensity of the G and 2D Raman peaks. This combination fingerprints graphene amongst all other carbon allotropes. We demonstrate that the Raman spectrum evolution with increasing number of layers reflects the evolution of the electronic structure and electron-phonon interactions. This makes Raman spectroscopy is a quick, high-throughput, non-destructive technique for the unambiguous identification of graphene layers. Finally we discuss the implications for the interpretation of the Raman spectra of single and double wall nanotubes. 1. A. C. Ferrari et al. arXiv:cond-mat/0606284 |
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