Extrusion of single-wall carbon nanotubes via formation of small particles condensed near an arc evaporation source

Single-wall (SW) tubes were produced by co-evaporation of carbon and lanthanum in helium gas and examined by transmission electron microscopy (TEM). TEM samples were collected directly from a space near the arc evaporation source during evaporation. SW tubes growing radially from compound particles were observed 4 cm above the source, but not 2 cm. The ‘sea urchin’-like morphology of these tubes were similar to those observed for soot deposited on the inner walls of the reaction chamber, suggesting that soot particles were formed first in the gas phase and SW tubes grew from them before deposition on the chamber wall. The temperature distribution and flow velocity of convection around the source are used for discussion of the growth mechanism of the SW tubes.