Diameter control of single-walled carbon nanotubes

Laser furnace technique has been used for diameter selective formation of single-walled carbon nanotubes (SWNTs) using NiCo, RhPt and RhPd catalysts. Particularly RhPd catalyst can produce very thin SWNTs in high yield. In this work, we investigated the furnace temperature dependence for each catalyst to control the diameter of SWNTs more strictly. Further, we investigated the effect of the gas flow velocity to see the growth time of SWNTs. When the how velocity was changed from 1.2 to 12 mm/s, the diameter distributions of the SWNTs obtained were changed significantly. This result suggests that the nucleation and the growth of SWNTs are much slower than the fullerene formation. Using the slow growth nature of SWNTs, there is a possibility of further diameter control of SWNTs. (C) 2000 Elsevier Science Ltd. All rights reserved.