In September, Mitra and materials scientist Philip Wong demonstrated a long-sought alternative: the first carbon nanotube (CNT) computer, built from transistors made not from silicon, but from single-atom-thick straws of carbon, called carbon nanotubes. Carbon nanotubes are only about 1 or 2 nanometers in diameter, but their fundamental electronic properties make it possible to send strong signals using far smaller transistors than is possible with silicon.
Because CNT devices use about a tenth as much power as comparable silicon systems, they could one day offer substantial energy savings, too. But don’t expect to go weeks without recharging your phone anytime soon: Mitra and Wong’s CNT computer has only 178 transistors, compared with the billions of transistors that comprise today’s complex silicon circuits. And it can perform only simple tasks, like adding numbers. The Stanford researchers compare their achievement to the first silicon computers built in the early 1970s. “This is just the beginning,” Mitra says.
[This article originally appeared in print as "Test Tubes: A Computer Powered by Carbon."]