Patent ID: 8246927

Claim:
A method of producing carbon nanotubes on a substrate, the method comprising: vacuum-exhausting, to less than or equal to 10 −2 Torr, a reaction vessel tube interior containing iron chloride and silicon oxide; disposing in the reaction vessel tube interior a hollow substrate having an inner wall, wherein the silicon oxide is disposed on a surface of the inner wall, wherein the substrate comprises a circular or polygonal cross-sectional configuration; heating the reaction vessel tube interior to a temperature in a range of 700° C.-900° C. while maintaining a pressure of the reaction vessel tube interior to less than or equal to 10 −2 Torr; bleeding acetylene into the reaction vessel tube interior at a supply pressure within a range of 0.1 Torr-50 Torr, wherein, at a time of start of bleeding acetylene, the pressure of said acetylene is set to be lower than the supply pressure; and growing the carbon nanotubes from iron carbide that is formed by a chemical vapor-phase reaction in the presence of the iron chloride provided at the inner wall.