Vertically aligned carbon nanotube growth from Ni nanoparticles prepared by ion implantation

Vertically aligned carbon nanotubes (CNTs) were synthesized from Ni nanoparticles prepared by ion implantation. Ni ions were implanted at 30 keV into thermally grown SiO2 substrates using a focused-ion-beam. High-density nanoparticle formation was investigated with high doses up to 5.0 × 1017 ions/cm2. Dense Ni nanoparticles in the order of 1011–1012 cm− 2 were obtained on a SiO2 substrate, and the particle density and diameter were controlled by post-implantation annealing. Particles annealed at 700 °C led to vertically aligned CNTs. Interestingly, catalysts were longer along the vertical axis and the lower half of the Ni particle was buried in SiO2.