Computer engineers are forever trying to make microchips smaller and more efficient. So far, essentially all resulting improvements (smarter smartphones, more powerful laptops, and the like) have come from better use of traditional silicon. But last January scientists at IBM’s T. J. Watson Research Center showed that a different material—cylinder-shaped molecules known as carbon nanotubes—may be the chip of the future.
Computer chips are made of transistors, which work by letting current flow through a channel only when voltage is applied to a gate, IBM researcher Aaron Franklin explains. “The thinner the channel or semiconductor material, the easier it is to control the current.” As silicon transistors are scaled down, Franklin says, the gate becomes less effective at controlling the current. Carbon nanotubes, one-tenth to one-hundredth the thickness of the smallest silicon transistors, remain functional at smaller scales.
“The carbon nanotube transistor carries over four times the electrical current density of the best similarly scaled silicon-based transistor,” Franklin says. “This can yield a technology that uses much less power while delivering enhanced performance.” In October, IBM announced they fit 10,000 carbon nanotube transistors onto a single chip, bringing nanotube-based computers closer to reality.
