Casting yields non-carbon nanotubes

Researchers from the University of California at Berkeley have developed a method of making minuscule tubes of gallium nitride that have useful electrical and optical properties.

The tiny tubes, which have diameters as small as 30 nanometers, are semiconducting, and, unlike more common carbon nanotubes, are also luminescent in the ultraviolet and blue light ranges. Thirty nanometers is about 30 times smaller than the diameter of E. coli bacterium.

The gallium nitride nanotubes could be used in microscopic electronic and optoelectronic devices, and in nanofluidics chips that sense and separate tiny traces of chemicals and biological material.

The researchers cast the gallium nitride tubes by depositing layers of a chemical vapor on zinc oxide nanowires. They heated and evaporated the zinc oxide to leave ordered arrays of nanotubes.

Nanotubes of different materials could be made using the same basic method, according to the researchers.

The method could be used in practical applications within five years, according to the researchers. The work appeared in the April 10, 2003 issue of Nature.