Effect of nanowire catalyst for carbon nanotubes growth by ICP-CVD

Aligned multi-walled carbon nanotubes (CNTs) fully filled with Fe, Co, and Ni were synthesized by inductively coupled plasma chemical vapor deposition (ICP-CVD) using nanowires as catalysts. The nanowires were prepared by electroplating using anodized alumina oxide (AAO) as a template. By properly selecting the length of nanowire (420 +/- 20 nm), CNTs fully filled with metal catalyst can be directly obtained. The effect of nanowires (Fe, Co and Ni) on growth of aligned CNTs is also systematically studied. It is found that the catalyst has a strong effect on the nanotube alignment and crystallinity. The CNTs catalyzed by Ni and Fe have better alignment and higher degree of graphitization, whereas those from Co show a little curled character in the tips and somewhat tangle between CNTs. In the field emission test, the CNTs filled with Ni, Fe and Co show low turn-on field about 1, 1.1 and 1.5 V/mu m, respectively. Besides low turn-on field, the CNTs synthesized by this method also have a high emission current density (larger than 10 mA/cm(2)). (c) 2004 Elsevier B.V. All rights reserved.