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Barreiro A.,CIN2 ICN CSIC Barcelona | Barreiro A.,Technical University of Delft | Rurali R.,CSIC - Institute of Materials Science | Hernandez E.R.,CSIC - Institute of Materials Science | Bachtold A.,CIN2 ICN CSIC Barcelona
Small | Year: 2011

The reversible atomic-mass transport along graphene devices has been achieved. The motion of Al and Au in the form of atoms or clusters is driven by applying an electric field between the metal electrodes that contact the graphene sheet. It is shown that Al moves in the direction of the applied electric field whereas Au tends to diffuse in all directions. The control of the motion of Al is further demonstrated by achieving a 90° turn, using a graphene device patterned in a crossroads configuration. The controlled motion of Al is attributed to the charge transfer from Al onto the graphene so that the Al is effectively charged and can be accelerated by the applied electric field. To get further insight into the actuation mechanism, theoretical simulations of individual Al and Au impurities on a perfect graphene sheet were performed. The direct (electrostatic) force was found to be ∼1 pN and dominant over the wind force. These findings hold promise for practical use in future mass transport in complex circuits. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Leconte N.,Catholic University of Louvain | Moser J.,CIN2 ICN CSIC Barcelona | Ordejon P.,CIN2 ICN CSIC Barcelona | Tao H.,CIN2 ICN CSIC Barcelona | And 8 more authors.
ACS Nano | Year: 2010

We present a multiscale ab initio study of electronic and transport properties of two-dimensional graphene after epoxide functionalization via ozone treatment. The orbital rehybridization induced by the epoxide groups triggers a strong intervalley scattering and changes dramatically the conduction properties of graphene. By varying the coverage density of epoxide defects from 0.1 to 4%, charge conduction can be tuned from a diffusive to a strongly localized regime, with localization lengths down to a few nanometers long. Experimental results supporting the interpretation as a metal - insulator transition are also provided. © 2010 American Chemical Society.

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