Method to Grow Ultra Long Carbon Nanotubes With Modified Gas-Flow Injector

University of California Irvine  Nanotechnology Group Leader Professor Peter J. Burke and Zhen Yu have developed systems for synthesizing ultra long carbon nanotubes comprising one or more metal underlayer platforms that allow the nanotube  to grow freely suspended from the substrate. A modified gas-flow injector is used to reduce the gas flow turbulence during nanotube growth. Nanotube electrodes are formed by growing arrays of aligned nanotubes between two metal underlayer platforms.

The systems earned U.S. Patent 7,718,224 for the Regents of the University of California (Oakland, CA)

Arrays of long, straight nanotubes can be grown via the methods using a single furnace system, without the need for rapid heating. In a preferred embodiment, the single furnace system comprises a modified CVD reaction chamber which reduces the turbulence of the gas flow of the hydrocarbon source provided during the growth phase. The reduced turbulence creates an enhanced environment for ultra-long nanotube formation.

In addition, a raised platform, comprising an underlayer of metal, is deposited onto a substrate. The raised platform allows the nanotube to grow freely suspended from the substrate in the low turbulence gas flow. This reduces any steric force impedance caused by the substrate and enables the nanotube to be grown to lengths on the order of centimeters.

In a preferred embodiment, the metal underlayer is comprised of a conductive metal such as gold. Using the methods described herein, the nanotube is able to grow from one metal underlayer platform to another such platform. The nanotube is thereby connected at both ends to a conductive material and forms a nanotube electrode without the need for a post nanotube formation processing step.