Carbon nanotubes and method of manufacturing same, electron emission source, and display

Abstract

The present invention provides carbon nanotubes perpendicularly and densely deposited over a wide area of a substrate. The carbon nanotubes are manufactured by supplying alternating-current power at a specific frequency between an anode and a cathode disposed in a reactor, and causing plasma to be generated between the anode and the cathode by introducing mixed gas containing an aliphatic hydrocarbon having 1-5 carbon atoms and hydrogen or mixed gas containing an aromatic hydrocarbon and hydrogen. The substrate is disposed between the anode and the cathode and held at a distance two times or less of the mean free path of a hydrocarbon cation from the anode.

What is claimed is:  
     
         1 . Carbon nanotubes perpendicularly and densely deposited on a substrate, which are obtained by plasma processing in which the temperature of the substrate is maintained at about 500° C. or less.  
     
     
         2 . A method of manufacturing carbon nanotubes comprising supplying alternating-current power at a specific frequency between an anode and a cathode disposed in a reactor, and causing plasma to be generated between the anode and the cathode by introducing mixed gas containing an aliphatic hydrocarbon having 1-5 carbon atoms and hydrogen or mixed gas containing an aromatic hydrocarbon and hydrogen, thereby allowing carbon nanotubes to be deposited on a substrate disposed between the anode and the cathode and held at a distance two times or less of the mean free path of a hydrocarbon cation from the anode.  
     
     
         3 . The method of manufacturing carbon nanotubes according to  claim 2 , wherein the distance between the anode and the substrate is 20 cm or less.  
     
     
         4 . The method of manufacturing carbon nanotubes according to  claim 2 , wherein the distance between the anode and the substrate is 10 cm or less.  
     
     
         5 . The method of manufacturing carbon nanotubes according to  claim 2 , wherein the specific frequency is  13 . 56  MHz.  
     
     
         6 . The method of manufacturing carbon nanotubes according to  claim 2 , wherein the aliphatic hydrocarbon having 1-5 carbon atoms is a saturated aliphatic hydrocarbon having 1-5 carbon atoms or an unsaturated aliphatic hydrocarbon having 1-5 carbon atoms.  
     
     
         7 . The method of manufacturing carbon nanotubes according to  claim 2 , wherein the aromatic hydrocarbon is benzene, toluene, or xylene.  
     
     
         8 . The method of manufacturing carbon nanotubes according to  claim 2 , wherein a metal, an alloy, a metal complex, or a metal compound is caused to adhere to the substrate as a catalyst.  
     
     
         9 . The method of manufacturing carbon nanotubes according to  claim 8 , wherein the catalyst is at least one of a metal, an alloy, or a metal compound of iron, cobalt, nickel, tungsten, platinum, rhodium, and palladium.  
     
     
         10 . The method of manufacturing carbon nanotubes according to  claim 2 , wherein a magnetic field is applied by disposing a magnet so that magnetic force occurs in a direction perpendicular to the substrate.  
     
     
         11 . The method of manufacturing carbon nanotubes according to  claim 2 , wherein the pressure of the mixed gas is 1 to 50 Pa.  
     
     
         12 . An electron emission source in which emitters are disposed between a cathode electrode and a gate electrode and electrons are emitted from the emitters by applying a voltage between the cathode electrode and the gate electrode, wherein the emitters comprise the carbon nanotubes according to  claim 1 .  
     
     
         13 . A display comprising the electron emission source according to  claim 12.