We present Raman spectroscopy measurements on single- and few-layer graphene flakes. Using a scanning confocal approach we collect spectral data with spatial resolution, which allows us to directly compare Raman images with scanning force micrographs. Single-layer graphene can be distinguished from double- and few-layer by the width of the D' line: the single peak for single-layer graphene splits into different peaks for the double-layer. These findings are explained using the double-resonant Raman model based on ab-initio calculations of the electronic structure and of the phonon dispersion. We investigate the D line intensity and find no defects within the flake. A finite D line response originating from the edges can be attributed either to defects or to the breakdown of translational symmetry.
@article{arxiv.cond-mat/0607562,
title = {Spatially Resolved Raman Spectroscopy of Single- and Few-Layer Graphene},
author = {D. Graf and F. Molitor and K. Ensslin and C. Stampfer and A. Jungen and C. Hierold and L. Wirtz},
journal= {arXiv preprint arXiv:cond-mat/0607562},
year = {2015}
}