Characterizing the maximum number of layers in chemically exfoliated graphene

Author(s)
Péter Szirmai, Bence G. Márkus, Julio C. Chacón-Torres, Philipp Eckerlein, Konstantin Edelthalhammer, Jan M. Englert, Udo Mundloch, Andreas Hirsch, Frank Hauke, Bálint Náfrádi, László Forró, Christian Kramberger, Thomas Pichler, Ferenc Simon
Abstract

An efficient route to synthesize macroscopic amounts of graphene is highly desired and bulk characterization of such samples, in terms of the number of layers, is equally important. We present a Raman spectroscopy-based method to determine the typical upper limit of the number of graphene layers in chemically exfoliated graphene. We utilize a controlled vapour-phase potassium intercalation technique and identify a lightly doped stage, where the Raman modes of undoped and doped few-layer graphene flakes coexist. The spectra can be unambiguously distinguished from alkali doped graphite, and modeling with the typical upper limit of the layers yields an upper limit of flake thickness of five layers with a significant single-layer graphene content. Complementary statistical AFM measurements on individual few-layer graphene flakes find a consistent distribution of the layer numbers.

Organisation(s)
Electronic Properties of Materials
External organisation(s)
Budapest University of Technology and Economics, Yachay Tech University, Freie Universität Berlin (FU), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universität Wien, École polytechnique fédérale de Lausanne
Journal
Scientific Reports
Volume
9
No. of pages
10
ISSN
2045-2322
DOI
https://doi.org/10.1038/s41598-019-55784-6
Publication date
12-2019
Peer reviewed
Yes
Austrian Fields of Science 2012
Materials physics, Surface physics, Solid state physics
ASJC Scopus subject areas
Portal url
https://ucris.univie.ac.at/portal/en/publications/characterizing-the-maximum-number-of-layers-in-chemically-exfoliated-graphene(868072c3-6628-4a07-b0b9-90146b61c2db).html