Free-standing and aligned carbon nanotubes and synthesis thereof
US6863942B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 1999 |
| Grant date | Mar 8, 2005 |
| Priority date | — |
| Expiry date | Jun 18, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/139
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
One or more highly-oriented, multi-walled carbon nanotubes are grown on an outer surface of a substrate initially disposed with a catalyst film or catalyst nano-dot by plasma enhanced hot filament chemical vapor deposition of a carbon source gas and a catalyst gas at temperatures between 300° C. and 3000° C. The carbon nanotubes range from 4 to 500 nm in diameter and 0.1 to 50 μm in length depending on growth conditions. Carbon nanotube density can exceed 104 nanotubes/mm2. Acetylene is used as the carbon source gas, and ammonia is used as the catalyst gas. Plasma intensity, carbon source gas to catalyst gas ratio and their flow rates, catalyst film thickness, and temperature of chemical vapor deposition affect the lengths, diameters, density, and uniformity of the carbon nanotubes. The carbon nanotubes of the present invention are useful in electrochemical applications as well as in electron emission, structural composite, material storage, and microelectrode applications.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.