Controlled growth of carbon nanotubes over cobalt nanoparticles by thermal chemical vapor deposition

Controlled growth of carbon nanotubes (CNTs) has been achieved by thermal chemical vapor deposition of acetylene gas over nanometer-sized cobalt particles. The well-aligned CNTs, which have a uniform diameter and high purity, are synthesized over cobalt nanoparticles distributed on substrates of large area. The alignment, density, and diameter of the CNTs are easily controlled by adjusting the density of the cobalt nanoparticles. Moreover, growth rate, density, diameter, and crystallinity of CNTs grown over the cobalt nanoparticles are also well controlled by the growth temperature. Our results demonstrate that the controlled growth of CNTs can be effectively realized by adjusting cobalt nanoparticles and growth temperature.