Carbon nanotube manufacturing method

Abstract

In a carbon nanotube manufacturing method, a substrate made of a carbon-containing metal material is arranged in a reactor in which a carbon source gas has been introduced. A plurality of carbon nanotubes are grown at a first temperature by chemical vapor deposition. Thereafter, the substrate is heated at a second temperature lower than the first heating temperature to grow the plurality of carbon nanotubes longer on the substrate.

1 . A carbon nanotube manufacturing method of arranging a substrate made of a carbon-containing metal material in a reactor in which a carbon source gas has been introduced, and growing a plurality of carbon nanotubes at a first temperature by chemical vapor deposition, and 
 thereafter heating the substrate at a second temperature lower than the first heating temperature to grow the plurality of carbon nanotubes longer on the substrate.    
     
     
         2 . A method according to  claim 1 , wherein at least a surface of the substrate is made of a metal material containing any one of iron, nickel, cobalt, and chromium.  
     
     
         3 . A method according to  claim 1 , wherein the first temperature is 750° C. to 1,000° C., and the second temperature is 500° C. to 750° C.  
     
     
         4 . A method according to  claim 1 , wherein the carbon source gas is one gas selected from the group consisting of carbon monoxide, acetylene, ethylene, ethane, propylene, propane, and methane gases.