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Radio frequency magnetron sputtering has been used for the synthesis of aligned carbon nanotubes (CNTs) on a SiO2∕Si substrate, with simultaneous in situ catalyst deposition. This method allows the use of substrates without the need of a surface predeposition of catalytic particles. In particular, among the metals considered, we observed the formation of CNTs using W or Ni as catalysts. Only in the case of Ni did we find that the CNTs are aligned along the target-substrate direction, unlike the randomly oriented CNTs observed when W was used as catalyst. Scanning and transmission electron microscopies show that the catalytic Ni nanoparticle is found mostly on the tip of the obtained bamboolike CNTs, while W nanoparticles are encapsulated inside hollow nanotubes, at different points along their length. We ascribe not only the observed structural differences to the size of the W and Ni particles but also to a …
Publication date: 
1 Dec 2007

S Scalese, V Scuderi, V Privitera, A Pennisi, F Simone

Biblio References: 
Volume: 102 Issue: 11 Pages: 114905
Journal of Applied Physics