The Use of NH_3 to Promote the Production of Large-Diameter Single-Walled Carbon Nanotubes with a Narrow {n,m) Distribution

摘要

We demonstrate here a simple and effective (n,m)-selective growth of single-walled carbon nanotubes (SWCNTs) in an aerosol floating catalyst chemical vapor deposition (CVD) process by introducing a certain amount of ammonia (NH_3). Chiralities of carbon nanotubes produced in the presence of 500 ppm NH_3 at 880 ℃ are narrowly distributed around the major semiconducting (13,12) nanotube with over 90% of SWCNTs having large chiral angles in the range 20°-30°, and nearly 50% in the range 27°-29°. The developed synthesis process enables chiral-selective growth at high temperature for structurally stable carbon nanotubes with large diameters.