Growth of vertically aligned carbon nanotube bundles using atmospheric-pressure microplasma

Vertically aligned bundles of multiwalled carbon nanotubes (MWNTs) were grown on the tip of a ø0.5 mm nickel wire using an atmospheric-pressure microplasma (APμP) generated by a RF-powered pipe electrode. A CH₄ and H₂ gas mixture was used for the source gas, and the nickel wire used as the substrate was negatively biased to heat it by ion bombardment. At a ratio of CH₄ : H₂ = 1 : 35, a RF power of 6 W, a DC bias voltage of -100 V and a growth time of 2 min, the tip of the nickel wire was covered by bamboo-like MWNT bundles, whose diameter and length were about 600 nm and 2-3 urn, respectively. Each bundle consisted of about 1500 tubes with diameters of 10-25 nm. The growth temperature of the MWNT bundles wasapproximately 500°C.