Methods for producing and using catalytic substrates for carbon nanotube growth

Abstract

A catalyst material for carbon nanotube synthesis includes a uniform dispersion of host particles on a substrate. The host particles themselves include catalyst nanoparticles that are effective to catalyze nanotube syntheses reactions and provide nucleation sites. Methods for preparing a catalyst material includes co-sputtering a catalytic species and a host species to directly form the catalyst material. Methods for synthesizing generally aligned nanotubes are also provided. In these methods host particles comprise alumina and the catalyst nanoparticles comprise iron. Also in these methods nanotube synthesis is achieved in an atmosphere including a carbon-containing gas and water vapor.

1 . A method for preparing a catalyst material for carbon nanotube synthesis, comprising: 
 co-depositing on a substrate a catalytic species and a host species to form a uniform dispersion of host particles including catalyst nanoparticles.    
     
     
         2 . A method for preparing a catalyst material for carbon nanotube synthesis, comprising: 
 co-depositing on a substrate a catalytic species and a host species to form a dispersion of catalyst nanoparticles on a host material.    
     
     
         3 . A method of synthesizing generally aligned carbon nanotubes, comprising: 
 forming a catalytic material on a substrate by co-depositing a catalytic species and a host species; and    growing the generally aligned carbon nanotubes in a direction substantially perpendicular to a plane defined by the substrate by passing a carbon-containing gas over the catalytic material on the substrate at an elevated temperature.    
     
     
         4 . The method of  claim 3  wherein the catalytic species comprises Fe and the host species comprises Al 2 O 3 .  
     
     
         5 . The method of  claim 3  wherein the catalytic material formed by the co-deposition includes a uniform dispersion of host particles having catalyst nanoparticles on the surfaces thereof.  
     
     
         6 . The method of  claim 3  wherein the carbon-containing gas includes C 2 H 4 .  
     
     
         7 . The method of  claim 3  wherein the carbon-containing gas also includes water vapor.  
     
     
         8 . The method of  claim 3  wherein growing the generally aligned carbon nanotubes includes a heating ramp step followed by a growth step.  
     
     
         9 . The method of  claim 8  wherein the heating ramp step includes passing H 2  gas over the substrate.  
     
     
         10 . The method of  claim 8  wherein the growth step includes passing C 2 H 4  and water vapor together over the substrate.