Abstract Submitted to the    NANOTUBE'04 Conference:

An oxy-acetylene combustion flame method has been widely studied for diamond synthesis since the technological development by Hirose et al. in 1988[1]. In this work, we demonstrate the catalytic synthesis of carbon nanotubes (CNTs) using this simple technique. A Ni-Co thin film is deposited as a catalyst on the substrate surface. The O2/C2H2 gas ratio and the substrate temperature are the key parameters to obtain the CNTs. The straight CNTs obtained at high substrate temperature range in large amount have a perfect hollow structure with well-graphitized graphene layers, similar to the ones grown by arc-discharge. Under certain experimental condition, we observed a formation of polyhedral crystals around these straight CNTs. Although the polyhedral crystals can be grown directly from substrate surface toward the flame source without catalyst [2], these are formed selectively around the CNTs in the presence of the catalyst because of a resemblance of these two structures consisting of the cylindrical graphitic layers. This fact is useful to control the formation of polyhedral crystals by a pre-deposition of CNTs. In addition to the industrial large yield synthesis, this technique can be applied also for local deposition, such as on the tip of STM probe.

[1] Y. Hirose and K. Komaki, Eur. Pat. EP 0 324 538 A1 (1988)
[2] H. Okuno, J.-F. Deprés, A. Palnichenko, J.-P. Issi and J.-C. Charlier, submitted to Carbon (2004)