Carbon nanotubes have continued to excite the material science field because of their proliferating array of allotropes — different forms of the material — all with potential. Dr. Guha complimented the Stanford group for maintaining its focus on a single engineering advance.

Currently, semiconductor industry leaders can make integrated silicon circuits with a feature size of 22 nanometers, roughly 4,000 of which could be spread across the width of a human hair. With the arrival of a new generation of smaller transistors roughly every two years, the industry generally believes that silicon will be scaled down to a limit of 5-nanometer transistors sometime after 2020.

The constant shrinking of transistor size over the last half-century has been important because it has significantly lowered the cost of computing, making it possible to build ever more powerful computers that are faster and cheaper, and consume less power with each generation.

While Intel has been generally circumspect about what material technology it plans to turn to when silicon ceases to “scale” down to smaller transistor sizes, I.B.M. has been more vocal and optimistic about the potential for carbon nanotubes.

The company has recently succeeded in creating an inverter, a basic logic element used in electronic circuits, using two different types of carbon nanotube transistors, and plans to demonstrate the device at a technical meeting at the end of the year.

The researchers said that their advance was not a scientific breakthrough, but it was a significant demonstration of the ability to work with a material other than silicon with great precision.

They also stressed that their research project was entirely compatible with industry-standard manufacturing processes based on silicon. This suggests that in the future it will be possible to build hybrid chips using carbon nanotubes at particular locations, and thus extend the life of silicon in computing.

The researchers said they were proud of their tiny prototype.

“This is a general computer and we can do anything with it,” said Max Shulaker, a Stanford graduate student who is a leading member of the research group. “We could in principle run 64-bit Windows, but it would take millions of years.”