In the hype-filled world of nanotechnology, Phaedon Avouris, head of IBM Research's nanoscience and technology group, has a reputation as a meticulous and somewhat skeptical scientist. By his own description, he is one of those researchers whom reporters call to get a "realistic assessment" of the latest nanotech breakthrough. These days, though, the IBM chemist sounds uncharacteristically upbeat.

The reason for his excitement can be seen in a microscopic image recently produced in his lab. It shows a thin thread draped over several thick gold electrodes. What is not so apparent is that the thread, a single carbon nanotube, has been modified and positioned so that it forms two types of transistors, each a few nanometers (billionths of a meter) in diameter- a hundred times smaller than the transistors now found on computer chips. What's more, the nanotube transistors work together as a logic gate, the fundamental computer component responsible for selectively routing electrical signals, transforming them into meaningful ones and zeroes.