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HP Researchers Develop New Logic Device of Molecular Size

By John Markoff

The New York Times -- SAN FRANCISCO

A group of Hewlett-Packard researchers will report Tuesday that they have created a molecular-scale alternative to the transistor. The new device could increase the viability of a new generation of ultrasmall electronics that may one day be smaller than what is possible with today’s silicon-based technology.

In an article to be published Tuesday in the Journal of Applied Physics, three researchers at the quantum science research group of Hewlett-Packard Labs, based in Palo Alto, Calif., describe how they have designed a device called a “crossbar latch,” making it possible to perform a type of logic operation that is essential to the functions of a modern computer.

The advance is significant, according to scientists, because for the first time it provides molecular computer designers with a complete array of logic devices to develop the new technology.

“Their latch demonstration experiment is significant and a big step forward for molecular-scale electronics,” said James C. Ellenbogen, a scientist and member of Mitre Corp.’s nanosystems group in McLean, Va.

The new device consists of a wire that is crossed by two other wires. The resulting junctions serve as switches that are only a few atoms across and can be programmed by a repeatable set of electrical pulses. Standard electronic devices require conventional transistors to perform the same operation.

After a burst of progress in molecular electronics in the late 1990s, there has been some industry skepticism about whether the field might ever be refined to the point that it could replace conventional microelectronics.

While the technology is not ready for commercialization, the Hewlett-Packard announcement is certain to re-energize the field. The researchers, Philip J. Kuekes, Duncan R. Stewart and R. Stanley Williams, said they believed their technology could be available after the end of this decade.

Currently, the semiconductor industry’s most advanced manufacturing process is based on a 90-nanometer minimum feature size: About 1,000 transistors made using this process would fit in the width of a human hair.

The Hewlett-Packard researchers said they began to focus on molecular electronics a number of years ago because they realized that traditional semiconductor manufacturing techniques would eventually be unable to produce the ever-faster speeds that advanced computing requires.

“As things shrink, it gets hard,” Kuekes said, referring to problems of heat and quantum mechanics that plague manufacturers of the smallest transistors. Not only do these devices leak current in the form of heat, but it also becomes increasingly difficult to determine whether a switch is on or off.