[en] We present Raman spectroscopy measurements on single- and few-layer graphene flakes. By 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.
Disciplines :
Physics
Author, co-author :
Graf, D.; ETH Zurich > Solid State Physics Laboratory
Molitor, F.; ETH Zurich > Solid State Physics Laboratory
Ensslin, K.; ETH Zurich > Solid State Laboratory
Stampfer, C.; ETH Zurich > Micro and Nanosystems
Jungen, A.; ETH Zurich > Micro and Nanosystems
Hierold, C.; ETH Zurich > Micro and Nanosystems
WIRTZ, Ludger ; CNRS-UMR 8520 > Institute for Electronics, Microelectronics, and Nanotechnology
Language :
English
Title :
Spatially resolved raman spectroscopy of single- and few-layer graphene
Publication date :
2007
Journal title :
Nano Letters
ISSN :
1530-6984
eISSN :
1530-6992
Publisher :
American Chemical Society, Washington, United States - District of Columbia