IMPROVING CONDITIONS TOWARDS ISOLATING SINGLE-SHELL CARBON NANOTUBES

We report on some of the conditions during carbon sublimation which promote single-shell carbon nanotube formation. Using as a catalyst a mixture of two metals (Co and Pt) in the anode, we observe a higher density of single-shell carbon nanotubes than that found with cobalt alone. Using other mixtures (Co and Fe), the nanotube yield is always lower, and their formation is even hindered (Co and Ru). First attempts of vacuum annealing at high temperature on samples containing cobalt-catalyzed single-shell carbon nanotubes suggest that this might be a good way to eliminate the catalyst particles. We present high-resolution transmission electron microscopy images of samples obtained by such procedures.