Just when we thought computer chips couldn’t get any smaller, along comes a new technology that promises to build semi-conducting materials atom by atom.

Over the past half-century computers have transformed our lives in countless ways, calculating figures too complex for the unaided mind and facilitating previously impossible tasks. Another magic trick computers have been performing since their introduction is the fact that they are steadily getting smaller. The first computers of the 1940s were so large they took up whole buildings with their bulk. At the turn of the millennium the computational power of those unwieldy giants can fit easily into the circuitry of a hand-held calculator. What’s more, scientists are now predicting that computers will get even smaller. The key to this potential to fit more computational power into a smaller space comes in the form of nano-engineered carbon tubes, microscopic sheets of graphite folded into long, thin cylinders. Carbon nano-tubes serve as ideal conductors of computer signals at the microcosmic level. As an example of the relative size of these materials, which are only about ten atoms in width, to their silicon counterparts, consider that current technology allows chipmakers to print circuits that are 1,000 times thinner than a human hair. That’s pretty small right? Well, nano-engineered carbon tubes can conduct the same amount of information at a size that is actually 50,000 times smaller than a human hair.

The use of nano-engineering, the ability to engineer structures on the molecular scale, to create carbon tubes was first discovered by Japanese scientist S. Iijima in 1991. But the problem of separating clinging non-conducting metallic carbon nano-tubes that were created in the process from truly semi-conducting nano-tubes held up progress on developing the technology. The latest breakthrough has come in the form of a technique developed by scientists at IBM in which a voltage is run through the material, literally “blowing up” the useless metallic nano-tubes and leaving only the semi-conducting materials intact. This breakthrough has led IBM researchers like Phaedron Avouris to herald a coming age of molecular computers. “We have tested the physics, we know that it works, so it’s a matter of developing the technology.” Avouris comments, “If nothing else, we showed that it’s not as difficult as people thought.”

The advent of molecular-scale computer technology is an exciting and almost surreal prospect for the future of computers. Some scientists have even theorized that computers will be made small enough to be worn as jewelry. Avouris tends to be cautious about predicting this era anytime soon. He concedes that it may be decades before such things come to pass. Much more likely, he believes, is the emergence of computers that combine both nano-engineered carbon parts and traditional silicon components. “I think what you’re going to see is hybridization between silicon and nano-tube technologies.” He expects commercial applications of the hybrid devices will surface in a little more than a decade’s time.

Molecular computing, if it is ever realized, would make silicon-based computers seem like dinosaurs. Quite simply, utilizing a nano-tube microchip, as opposed to silicon, would multiply the storage density of computer chips by a staggering scale. In the words of Tom Theis, IBM’s director of physical sciences, “In this century we’ll be able to put millions of times more processing power into people’s hands for the same amount of money.” As an afterthought he adds, “I don’t know what we’ll do with that computational power.”

Sources: Future Computing: Faster than Silicon
Tim McDonald
Newsfactor, May 3, 2001
http://www.newsfactor.com/perl/story/?id=9453

The Incredible Shrinking Computer
John Teresko
Industry Week, June 11, 2001
http://www.industryweek.com/CurrentArticles/asp/articles.asp?ArticleID=1070