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Nano Lett ; 12(9): 4503-7, 2012 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-22871144


High-quality, large-area epitaxial graphene can be grown on metal surfaces, but its transport properties cannot be exploited because the electrical conduction is dominated by the substrate. Here we insulate epitaxial graphene on Ru(0001) by a stepwise intercalation of silicon and oxygen, and the eventual formation of a SiO(2) layer between the graphene and the metal. We follow the reaction steps by X-ray photoemission spectroscopy and demonstrate the electrical insulation using a nanoscale multipoint probe technique.

Cristalização/métodos , Grafite/química , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Rubídio/química , Dióxido de Silício/química , Condutividade Elétrica , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Propriedades de Superfície
Opt Express ; 13(18): 6899-904, 2005 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-19498709


We explore the functionalities of a generalized phase contrast (GPC) -based multiple-beam trapping system for the actuation of various microfabricated SiO2 structures in liquid suspension. The arrays of optical traps are formed using two counterpropagating light fields, each of which is spatially reconfigurable in both cross-sectional geometry and intensity distribution, either in a user-interactive manner or under computer supervision. Design of microtools includes multiple appendages with rounded endings by which optical traps hold and three-dimensionally actuate individual tools. Proof-of-principle demonstrations show the collective and user-coordinated utility of multiple beams for driving microstructured objects. The potential to integrate these optically powered microtools may lead to more complex miniaturized machineries - a closely achievable goal with the real-time reconfigurable optical traps employed in this work.