Processes for growing carbon nanotubes in the absence of catalysts

Abstract

Processes for increasing the production rate of single-wall carbon nanotubes using a disordered carbon target are disclosed. The processes use a disordered carbon target and include vaporization of the target in the presence of a non-oxidizing gas. The single-wall nanotubes produced can be incorporated into electronic devices such as diodes and transistors.

1 - 8 . (canceled) 
   
   
       9 . A process for making a single wall carbon nanotube comprising (a) providing a target having a density of 0.01 to 2 g/cm 3  comprising disordered carbon and a metal catalyst, wherein the disordered carbon consists essentially of carbon black, and wherein the disordered carbon has a density of less than 2.2 g/cm 3 ; (b) laser ablating the target at a temperature of between about 900° C. and 1500° C. and at a pressure of about 10 −3  Torr to about 10 +3  Torr in the presence of a non-oxidizing gas; and (c) forming a product comprising at least one single-wall carbon nanotube. 
   
   
       10 . The process of  claim 9  wherein the pressure is about 300 Torr to about 600 Torr. 
   
   
       11 . The process of  claim 9  wherein the temperature is about 1000° C. to about 1300° C. 
   
   
       12 . The process of  claim 9  wherein the non-oxidizing gas is selected from the group consisting of argon, neon, helium, nitrogen and mixtures thereof. 
   
   
       13 . A single-wall carbon nanotube produced by the process of  claim 9 . 
   
   
       14 . The process of  claim 9  wherein the catalytic metal comprises yttrium. 
   
   
       15 . The process of  claim 9  further comprising a step of subjecting a product comprising at least one single-wall carbon nanotube to additional cycles of vaporization and single-wall carbon nanotube formation. 
   
   
       16 . The process of  claim 9  further comprising a step of annealing the product.