Carbon wires expand nano toolkit

Scientists looking for building blocks to form electronics and machines that are not much bigger than molecules have gained a new tool. Researchers from Meijo University in Japan have found a way to make carbon nanowires that measure only a few carbon atoms across.

Carbon nanowires, like their well-studied cousins, carbon nanotubes, are very strong and have useful electrical properties. Because they are solid, they should be even stronger than nanotubes, according to the researchers. They could be used in nanoelectronics, as microscopic-machine parts, and in materials constructed molecule-by-molecule.

The researchers formed carbon nanotubes -- rolled-up sheets of carbon atoms -- by shooting a plasma arc between a pair of carbon electrodes in a hydrogen atmosphere. The hydrogen atoms kept the chemical bonds at the growing ends of the nanotubes open, and smaller carbon nanotubes grew inside larger ones; when the hollow core of a nanotube became too small to fit a tube, a single chain of atoms filled the core to form a nanowire.

Carbon nanowires could eventually be used in ultra-strong fibers, as friction-free bearings, and in space shuttle nose cones, according to the researchers.

Carbon nanowires could be used in practical applications in five to ten years. The work appeared in the May 6, 2003 issue of Physical Review Letters.