Incidence of multilayers in chemically exfoliated graphene

P. Szirmai, B. G. Márkus, J. C. Chacón-Torres, P. Eckerlein, K. Edelthalhammer, J. M. Englert, U. Mundloch, A. Hirsch, F. Hauke, B. Náfrádi, L. Forró, C. Kramberger, T. Pichler, F. Simon

An efficient route to synthesize macroscopic amounts of graphene is highly desired and a 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 distribution of the number of graphene layers in chemically exfoliated graphene. We utilize a controlled vapor-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 a modeling with the distribution 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.

Electronic Properties of Materials
Publication date
Austrian Fields of Science 2012
103018 Materials physics, 103020 Surface physics, 103009 Solid state physics
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