Tilted trenches turn out tiny wires

The challenge to making wires as narrow as 50 atoms across is finding a way to process the bits of metal gently enough. Standard fabrication processes can damage nanowires, which are a key component of nanotechnology.

Researchers from the University of California at Los Angeles, the University of California at Santa Barbara, and the California Institute of Technology have found a way to make arrays of closely-spaced and crossed metal and semiconductor nanowires.

The researchers etched a template of thin, alternating slices of two types of semiconductor with an atom beam that removed more of one type than the other, leaving narrow, closely spaced trenches. They tilted the template, coated its edges with an ultrathin layer of metal and pressed it onto a silicon wafer to transfer the metal. The resulting wires were as narrow as five nanometers -- 26 times narrower than Pentium chip transistors -- and spaced 15 nanometers apart.

The arrays could be used as extremely sensitive chemical sensors, high-frequency resonators in communications equipment, and ultrasmall computer circuits.

The method could yield practical sensors within five years and circuitry in a decade, according to the researchers. The work appeared in the March 13, 2003 issue of Sciencexpress.