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Graphene is a two-dimensionnal arrangement of carbon atoms in an hexagonal lattice. That gives it unusual band structure and therefore properties. In particular it is very strong, optically, transparent, highly conducting etc. Since the first measurement of its electrical properties Graphene has focused an intense effort of research because it is interesting for basic research but also because potential applications may become real quite soon (Samesung plans to use it in its touch screens). In 2010, André Geim and Kostia Novoselov were awarded the Nobel prize in physics for their pionneering work on graphene. Graphene is the bulding block of graphite and can be extracted from it using scotch tape. This method is not reproductible and does not allow to collect large area. Today, there are several other method to synthetize graphene. The most promissing is probably the Chemical Vapour Deposition assisted by a metal catalyst. The carbon precusor decomposes on the metallic layer and carbon atoms rearrange into graphene. We recently demonstrated that if the catalyst film is thin but not too thin, it break after some time leading to the formation of carbon nanotubes bellow the few layer graphene (see left picture). We showed that the nanotubes are epitaxially grown below the few graphene layers and that the interface has the form depicted on the right figure. The red particle represents the catalys metal. This type of material could be useful for future microelectonics, of for hydrogen storage as it combines the outstanding properties of both graphene and carbon nanotubes.
Read more on Cornell's arXiv.