Graphene Made by Mechanical Exfoliation of Graphite Intercalation Compound

We report a method of making few-layer graphene flakes by mechanically exfoliating SbCl 5 --graphite intercalation compounds (GICs). The number of layers of exfoliated graphene flakes had a particular distribution relevant to the stage structure of the GICs. The carrier doping of the few-layer graph...

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Bibliographic Details
Published inJapanese Journal of Applied Physics Vol. 51; no. 8; pp. 085101 - 085101-4
Main Authors Fukada, Seiya, Shintani, Yumi, Shimomura, Midori, Tahara, Fumiya, Yagi, Ryuta
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.08.2012
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Summary:We report a method of making few-layer graphene flakes by mechanically exfoliating SbCl 5 --graphite intercalation compounds (GICs). The number of layers of exfoliated graphene flakes had a particular distribution relevant to the stage structure of the GICs. The carrier doping of the few-layer graphene flakes was about two orders of magnitude smaller than that expected from the stoichiometry of the GICs. The measured electric mobility was comparable to that made from pristine graphite.
Bibliography:(001) X-ray diffraction measurement of graphite and SbCl 5 --GIC specimen with stages 2, 3, and 4 obtained using a diffractometer with Cu K$\alpha_{1}$ radiation. Numbers (N) indicated in the figure are peaks for (00N)-reflection. Optical micrograph of graphene flakes and thin graphite transferred on Si substrate covered with 3000 $Å$ of SiO 2 by the standard mechanical exfoliation method. Panels (a) and (b) are for GIC and pure graphite, respectively. Bars are 10 μm. Left panel: optical micrograph of an exfoliated GIC flake in which Types A and B coexisted, as outlined with a broken line. Right panel: EPMA result, indicating spatial distribution of Sb signal intensity. Histograms of green signal intensity measured for digitized RGB image of graphene flakes on Si substrate. G-signal intensity was offset by that of substrate. Measured flakes were chosen randomly. Type B flakes were analyzed. Numbers that are shown near peaks indicate the calibrated layer numbers of graphene. Dependence of resistivity on gate voltage for (a) bilayer graphene and (b) trilayer graphene. Red lines show results for graphene from SbCl 5 --GIC and black lines show those for pristine graphite. Spatial distribution of (a) Cl and (b) Sb concentrations measured using EPMA. SEM micrograph of measured area is shown in panel (c). Fluctuations of Sb and Cl signals indicated inhomogeneous distribution of SbCl 5 . Panel (d) is an illustration of a grafoil-like structure possibly formed near the surface.
ISSN:0021-4922
1347-4065
DOI:10.1143/JJAP.51.085101