Production of fullerenes by sputtering

• US 5,494,558 A
• Filed: 11/29/1994
• Issued: 02/27/1996
• Est. Priority Date: 08/12/1992
• Status: Expired due to Term

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Bunshah, Rointan F., Prakash, Shiva, Jou, Shyankay, Doerr, Hans J.
• Primary Examiner(s): NGUYEN, NAM X
• Application Number:
  US08/346,549
• Time in Patent Office: 455 Days
• Field of Search: 423/445, 423/446, 423/461, 204/192.12, 204/192.15, 204/192.1, 204/298.01, 204/298.09, 204/298.19
• US Class Current: 204/192.15
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01B 32/15 Nano-sized carbon materials
• CPC Class Codes: C01B 32/154 Preparation
• CPC Class Codes: C23C 14/0005 Separation of the coating from the substrate
• CPC Class Codes: C23C 14/0605 Carbon
• CPC Class Codes: C30B 23/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/02 Elements
• CPC Class Codes: Y10S 977/842 for carbon nanotubes or fullerenes

Abstract

A process and system for producing fullerenes by sputtering. A carbon target is sputtered to form a vapor of sputtered carbon atoms. The sputtered carbon atoms are quenched in an atmosphere of inert gas and deposited onto a collection substrate. The resulting carbon soot is extracted to recover fullerenes. The process produces carbon soot which is rich in C₇₀ and higher fullerenes.

Claims

1. A process for producing higher fullerenes comprising the steps of:

bombarding a carbon target with a sufficient amount of ions to sputter carbon atoms from said target to form a vapor of sputtered carbon atoms;

maintaining an atmosphere of inert gas into which said carbon atoms are sputtered to form said vapor of sputtered carbon atoms, said vapor of sputtered atoms being maintained at a pressure of between about 0.5 to 10 Torr;

depositing said sputtered carbon atoms onto a substrate to form a carbon soot which contains higher fullerenes and C₆₀ wherein the ratio of said higher fullerenes to C₆₀ is high; and

separating said higher fullerenes from said carbon soot.

2. A process for producing higher fullerenes according to claim 1 wherein said carbon target consists essentially of graphite.

3. A process for producing higher fullerenes according to claim 1 wherein the inert gas atmosphere into which said carbon atoms are sputtered consists essentially of helium and wherein said carbon target is bombarded with positively charged helium ions.

4. A process for producing higher fullerenes according to claim 1 wherein the step of depositing said sputtered carbon atoms comprises the steps of:

entraining at least a portion of said vapor of sputtered carbon atoms in a stream of inert gas; and

directing said stream of inert gas onto a chilled deposition substrate wherein said sputtered carbon atoms are deposited as said carbon soot.

5. A process for producing higher fullerenes according to claim 1 wherein said step of separating said higher fullerenes from said carbon soot comprises the steps of:

removing at least a portion of said carbon soot from said substrate; and

extracting said higher fullerenes from said carbon soot removed from said substrate by treating said removed soot with a solvent in which one or more of said fullerenes are soluble.

6. A process for producing higher fullerenes according to claim 5 wherein said solvent is selected from the group consisting of pentane, hexane, heptane, octane, benzene, toluene, xylene, carbon disulfide, carbon tetrachloride, pyridine, quinoline and trichloroethane and mixtures thereof.

7. A process for producing higher fullerenes according to claim 6 wherein said solvent is toluene.

8. A process for producing higher fullerenes according to claim 1 wherein said step of bombarding said carbon target with positive ions comprises magnetron sputtering of said carbon target.

9. A process for producing higher fullerenes according to claim 1 wherein said sputtered carbon atoms are deposited on a plurality of substrates which are located in spaced relation with respect to each other and with respect to said carbon target.

10. A system for producing higher fullerenes by sputter-deposition, said system comprising:

a sputtering vessel which includes walls defining a sputter-deposition zone;

a carbon target located within said sputter-deposition zone;

means for bombarding said carbon target with a sufficient amount of ions to sputter carbon atoms from said target to form a vapor of sputtered carbon atoms within said sputter-deposition zone;

means for maintaining an atmosphere of inert gas in said sputter-deposition zone at a pressure of between about 0.5 Torr and 10 Torr wherein said carbon atoms are sputtered into said zone to form said vapor of sputtered carbon atoms;

at least one substrate located within said sputter-deposition zone onto which said sputtered carbon atoms are deposited to form carbon soot which contains fullerenes wherein the ratio of higher fullerenes to C₆₀ is high; and

means for separating said higher fullerenes from said carbon soot.

11. A system for producing higher fullerenes by sputter-deposition according to claim 10 wherein said carbon target consists essentially of graphite.

12. A system for producing higher fullerenes by sputter-deposition according to claim 10 wherein said means for bombarding said carbon target comprises means for magnetron sputtering of said carbon target.

13. A system for producing higher fullerenes by sputter-deposition according to claim 10 wherein said system further comprises:

means for entraining at least a portion of said vapor of sputtered carbon atoms in a stream of inert gas; and

means for directing said stream of inert gas onto a chilled deposition substrate wherein said sputtered carbon atoms are deposited on said substrate as said carbon soot.

14. A system for producing higher fullerenes by sputter-deposition according to claim 10 wherein said means for separation said higher fullerenes from said carbon soot comprises:

means for removing at least a portion of said carbon soot from said substrate; and

means for extracting said higher fullerenes from said carbon soot removed from said substrate by treating said removed soot with a solvent in which one or more of said higher fullerenes are soluble.