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Nanotech studies could aid silicon chips

By SCOTT R. BURNELL, UPI Science News   |   May 1, 2002 at 5:51 PM
ARLINGTON, Va., May 1 (UPI) -- Research underway at federally funded nanotechnology centers, where academic and industry scientists explore manipulating matter at the atomic scale, might help computer chips avoid a developmental dead end, experts said during a conference Wednesday.

The conferees examined efforts at Nanoscale Science and Engineering Centers around the country. The centers are part of the National Nanotechnology Initiative, the government's focused effort to examine the world at the tiniest level -- a nanometer is to an inch what an inch is to 400 miles.

The NSEC at Cornell University in Ithaca, N.Y., focuses on roles nanostructures can play in information technology devices 10 to 15 years from now, said Robert Buhrman, a professor of applied physics and the center's director.

Continuing to make faster, more efficient chips relies on ever smaller circuit elements. Today's chip designers face barriers in how small they can effectively create such features.

The structures all have dimensions smaller than 100 nanometers and are based on both carbon and the silicon, which forms the basis of chips, he said.

"We view the opportunities in carbon nanoelectronics ... as a way to integrate carbon into the silicon world, not to replace the silicon world," Buhrman told the conference.

One possibility involves carbon nanotubes, basically rolled-up sheets of carbon only one atom thick. The tubes can exhibit electrical conductivity similar to copper but can handle much stronger currents without breaking down, Buhrman said, and could serve as connections between future circuit elements too small for copper wires.

The Cornell NSEC also examines how individual molecules might serve as circuit elements tens or hundreds of times smaller than today's chips, Buhrman said.

Similar work is going on at Columbia University's nanoscale facility in New York City, said Tony Heinz, a professor of electrical engineering and physics at the center.

Heinz's work focuses on developing a fuller understanding of the electrical properties of the organic molecules chemists can create. In many cases, assembling the molecules into gaps in a circuit pattern could be easier than today's chipmaking processes, he said.

Simply running a current through the gap would attract the molecules and once they fill the gap, the current drops to the point the attraction stops, making the procedure self-limiting, he said.

Another area of research at the Cornell NSEC deals with nanophotonics, structures that display optical properties. Buhrman said nanometer-sized crystals of lead-based materials, for example, emit the optimal wavelengths of light for all-optical computer networks.

The ability to transmit data via light, without having to switch from electric signals and back, could enable faster computer networks carrying hundreds of times more data.

Collaboration between Cornell and optical fiber maker Corning show lead nanocrystals can be embedded in quartz, the first step in creating an nanotechnology-powered optical amplifier, Buhrman said.

© 2002 United Press International, Inc. All Rights Reserved. Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI's prior written consent.
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