Dielectrophoretically assembled carbon nanotube-metal hybrid structures with reduced contact resistance

We report the bottom-up assembly of single-walled carbon nanotube interconnects between micro-fabricated gold electrodes by dielectropboresis followed by a post-dielectrophoretic deposition of metal from an aqueous Pd salt solution. The dielectrophoretic metal deposition along interconnects takes preferentially place at sites where high contact resistances occur. These create sufficiently high voltage drops, and thus, large field gradients which lead to a local deposition of metal. Since in turn the metal deposition leads to a reduction of the local resistances, the reported post-treatment process is self-regulating, that is, the deposition of metal stops when the contact resistances become sufficiently reduced. Applying this process to single interconnects of carbon nanotubes a reduction of the overall resistance below 1 M Omega has been achieved. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim