US Patent 7585484 - Control of CNT tip manufacture

http://www.freepatentsonline.com/7585484.html

Alteration of the tip shape and structure of carbon nanotubes can be useful to control the chemical functionalization of the tips or to enhance field emission properties. This patent from Tsinghua University and Hon Hai Precision teaches a CVD flow control method used to regulate such tip alteration. Claim 1 reads:

1. A method for synthesizing carbon nanotubes with desired tip structures, comprising the steps of:

introducing a carbon source gas flowing over a catalyst received in a reaction chamber;

continuously reducing an inner pressure in the reaction chamber with a predetermined pressure-reduction speed; and

forming carbon nanotubes with desired tip structures on the catalyst, the tip structures being related to the pressure-reduction speed.