Ex-situ synthesized nickel nanoparticles for multi-walled carbon nanotube growth on high aspect ratio substrates

An ink made from ex-situ synthesized nickel nanoparticles suspended in hexane is proposed as catalyst for the growth of carbon nanotubes onto high aspect ratio surfaces. The functionality of the ink as precursor has been at first checked onto standard flat surfaces such as silicon oxide onto a silicon wafer, were thick mats of multi-walled carbon nanotubes have been obtained from ink droplets on the surface. Tungsten electrodes, made from thin wires that have been electro-chemically etched to produce sharpened tips, have been treated by dip-coating using the same nanoparticle ink. On such samples, multi-walled carbon nanotubes have been grown directly on the metal surface with different surface coverage depending on the nickel nanoparticle concentration in the ink. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim