Nanotubes smash length record

Duke University researchers have found a way to make especially long, well-aligned carbon nanotubes. Nanotubes, which are rolled-up, single-atom-thick sheets of carbon, have great potential as components of nanomachines and nanoelectronics.

The researchers' method produces nanotubes as long as two millimeters, which is 100 times longer than previous efforts, according to the researchers. The nanotubes were 2.5 nanometers in diameter, or about the length of a row of 25 hydrogen atoms. A nanometer is one millionth of a millimeter.

The key to making the straight, long nanotubes is a hot flow of carbon monoxide and hydrogen gases. The researchers used tiny clusters of iron and molybdenum positioned on a small rectangle of silicon as a catalyst; the long nanotubes formed in the direction of the gas flow.

The researchers also reoriented the gas flow to make cross-connecting grids of nanotubes. Such patterns of tubes could form the basic building blocks of nanoscale circuitry. The nanotubes' length make them easier to handle; a single tube could even form several electronic components.

The technique should be perfected in two to five years, according to the researchers. The work appeared in the April 22, 2003 issue of the Journal of American Chemical Society.