The computer chips that physicist Marvin Cohen and his colleagues at the Lawrence Berkeley Laboratory have in mind are so small and powerful that four wine bottles could contain enough to store all the information in all the human brains in the world. A thread of the same circuits less than one-hundredth of an inch long could easily hold all the information in all the books ever written.
These theoretical computer circuits would be constructed from complex carbon molecules called nanotubes that have the same electrical properties as the silicon semiconductors used in most computers today. They would be a hundred times stronger than steel, as fast as a conventional supercomputer and, best of all, would assemble themselves. These are chips measured in nanometers: one billionth of a meter--the size of some viruses. They promise circuits 100 times smaller than the most miniature devices available today--computers that can be woven into clothing, painted onto walls, injected into the bloodstream or sprinkled like fairy dust in the air.
It is one vision of what lies beyond Silicon Valley, when the technology of conventional semiconductors has exhausted its possibilities and the cost of producing increasingly complex silicon chips becomes more than anyone can pay.
But scientists have yet to discover a way to assemble these molecules for nanocomputers into the flawless circuits that today's computers demand. It is not for want of trying. Already, scientists wielding electron beams like arc welders have built experimental structures thousands of times smaller than a human hair--gears that turn, pumps that operate, electric turbines only 60 microns in diameter that run on static electricity, transistors only 10 atoms in diameter.
IBM researchers recently built a working abacus in which carbon molecules slide along microscopic copper grooves. Not to be outdone, two Cornell University scientists crafted a guitar just 10 microns long, about the size of a single cell. They pluck its six silicon strings--each about 100 atoms wide--with an atomic force microscope.