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06 February 2002

Smaller, powerful computers move closer to reality

In another step up the ladder to a new generation of powerful small computers and electronic devices, two groups of researchers succeeded in making lattices that enable nanowires to work together with otherwise incompatible materials. Such mixed bundles are essential to making electronics and other devices on an increasingly smaller scale.

"This is a major advancement in the field of one-dimensional nanostructure research. The impact could be tremendous," said Peidong Yang, Ph.D., assistant professor in the Department of Chemistry at the University of California at Berkley and a faculty scientist in the Materials Science Division at Lawrence Berkeley National Laboratory.

A Swedish research team separately reported on the new development.

Based on the findings of both research groups, tiny components known as nanowires that meld a variety of materials could soon be routinely and cheaply built using little more than a special mixture of gases deposited on a foundation material.

The report by the U.S. team details how it fabricated "superlattice" nanowire that interweaves substances with different compositions and properties. As a result, well-defined junctions and interfaces with potentially important functionalities incorporate within individual nanowires.

Nanoengineers, by mixing and matching elements, hope to create new classes of nanoscale products or systems that would revolutionize everything from energy production to manufacturing and assembly. In the field of electronics and optics, mastery of these nanoscale "heterostructures" should lead to devices too small to see with the naked eye but equal to or better than today's hand-sized electronics.

The Swedish scientists working in the materials chemistry and solid state physics departments in Lund University's Nanometer Consortium used methods related to but different than their California peers. In both cases, manufacture is relatively straightforward and results in stable nanowires that can operate at room temperature, Yang said.

"Without a way of putting different materials together with a junction of some kind, we wouldn't have all the devices we take for granted, like transistors and [compact disc] lasers," he said.

But the California scientists have gone a step further: "We've successfully made nanoscale junctions within individual [nano]wires, putting different materials together, embedding junctions directly in the wires. The next step is to use the wires as submicroscopic components for various optoelectronic devices. These are definite first steps but critical ones," Yang said.

Today's PCs rely on a series of small junctions that connect components that have properties necessary for proper functioning. Given the laws of physics and real-world manufacturing demands, radically scaling down such functionality is difficult. The research findings in California and Sweden promise to make ultrasmall-scale devices practical.

The newly reported research should also help allay concerns of those worried that Moore's Law might not hold, considering the physical limits inherent in current approaches to computer chip design. The law, first postulated by Gordon Moore, a physical chemist and cofounder of Intel Corp., proposed that computer processing power would likely double every 18 months or so.