Wednesday, May 12, 2010

US Patent 7713589 - Improved CVD nanotube fabrication

Chemical vapor deposition is a technique used to grow carbon nanotubes from catalytic particles by exposing the catalysts to hydrocarbon gases at high temperatures. This patent from Hon Hai Precision teaches a way to lower the temperature of CVD nanotube growth while improving the speed and yield of growth. Claim 1 reads:

1. A method for making an array of carbon nanotubes, comprising the steps of:

(a) providing a substrate with a film of catalyst provided thereon;

(b) disposing the substrate in a reaction chamber;

(c) supplying a carrier gas into the reaction chamber and heating the reaction chamber to a predetermined temperature; and

(d) introducing a carbon source gas and a hydrogen gas into the reaction chamber separately and simultaneously;

the hydrogen gas being introduced such that the hydrogen gas has less of a distance to travel in the reaction chamber than does the carbon source gas to reach the substrate.