Manifestation of Charged and Strained Graphene Layers in the Raman Response of Graphite Intercalation Compounds

Author(s)
Julio Cesar Chacon Torres, Ludger Wirtz, Thomas Pichler
Abstract

We present detailed multifrequency resonant Raman measurements of potassium graphite intercalation compounds (GICs). From a well-controlled and consecutive in situ intercalation and high-temperature deintercalation approach the response of each stage up to stage VI is identified. The positions of the G and 2D lines as a function of staging depend on the charge transfer from K to the graphite layers and on the lattice expansion. Ab initio calculations of the density and the electronic band structure demonstrate that most (but not all) of the transferred charge remains on the graphene sheets adjacent to the intercalant layers. This leads to an electronic decoupling of these “outer” layers from the ones sandwiched between carbon layers and consequently to a decoupling of the corresponding Raman spectra. Thus, higher stage GICs offer the possibility to measure the vibrations of single, double, and multilayer graphene under conditions of biaxial strain. This strain can additionally be correlated to the in-plane lattice constants of GICs determined by X-ray diffraction. The outcome of this study demonstrates that Raman spectroscopy is a very powerful tool to identify local internal strain in pristine and weakly charged single and few-layer graphene and their composites, yielding even absolute lattice constants.

Organisation(s)
Electronic Properties of Materials
External organisation(s)
University of Luxembourg, Université Lille I - Sciences et Technologies
Journal
ACS Nano
Volume
7
Pages
9249-9259
No. of pages
11
ISSN
1936-0851
DOI
https://doi.org/10.1021/nn403885k
Publication date
10-2013
Peer reviewed
Yes
Austrian Fields of Science 2012
103020 Surface physics, 1030 Physics, Astronomy, 103009 Solid state physics, 103018 Materials physics
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/manifestation-of-charged-and-strained-graphene-layers-in-the-raman-response-of-graphite-intercalation-compounds(1867fd4d-8ca4-4757-86c1-741d8c2665f8).html