Synthesis of single-walled carbon nanotubes (C-SWNTs) with a plasma torch: a parametric study.

In this study, we examine, in detail, the synthesis of single wall carbon nanotubes (C-SWNTs) with a plasma torch, using molecular sources for both carbon and catalyst (typically a carbon-containing gas such as ethylene and ferrocene for the metal catalyst). A comparison of the results obtained by Raman spectroscopy, using two different excitation wavelengths, permitted us to evaluate the importance of certain experimental parameters affecting the quality of the samples; these include the growth temperature of the nanotubes, and the temperature gradient between the flame and the oven. We have found that our method provides results that are qualitatively similar to those obtained using arc and laser techniques: C-SWNTs mixed with catalyst nanoparticles and amorphous carbon.