The use of NH3 to promote the production of large-diameter single-walled carbon nanotubes with a narrow (n,m) distribution.

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 °C 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.