Electric Field Effect in Atomically Thin Carbon Films
Tóm tắt
We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10 13 per square centimeter and with room-temperature mobilities of ∼10,000 square centimeters per volt-second can be induced by applying gate voltage.
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Tài liệu tham khảo
I. L. Spain, in Chemistry and Physics of Carbon, P. L. Walker, P. A. Thrower, Eds. (Dekker, New York, 1981), pp. 119–304.
Other methods of preparing thin graphitic layers exist. The closest analogs of FLG are nanometer-sized patches of graphene on top of pyrolytic graphite ( 12 13 ) carbon films grown on single-crystal metal substrates ( 14 ) and mesoscopic graphitic disks with thickness down to ∼60 graphene layers ( 8 9 ).
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We believe that our thinnest FLG samples (as in Fig. 2A) are in fact zero-gap semiconductors because small nonzero values of δϵ found experimentally can be attributed to inhomogeneous doping which smears the zero-gap state over a small range of V g and leads to finite apparent δϵ.
M. R. Stan, P. D. Franzon, S. C. Goldstein, J. C. Lach, M. M. Zeigler, Proc. IEEE91, 1940 (2003).
Supported by the UK Engineering and Physical Sciences Research Council and the Russian Academy of Sciences (S.V.M. S.V.D.). We thank L. Eaves E. Hill and O. Shklyarevskii for discussions and interest.