Scientists Create World's First Carbon Nanotube Computer

Scientists have built a new computer. It's not just any computer, though; it was created with carbon nanotubes, a semiconductor material that has the potential to launch a new generation of electronic devices that run faster while using less energy.

Carbon nanotubes (CNTs) have long been considered to be a potential successor to the silicon transistor. But until now, researchers haven't been sure whether or not CNTs could fulfill the role scientists expected of them.

"People have been talking about a new era of carbon nanotube electronics moving beyond silicon," said Subhasish Mitra, one of the researchers, in a news release. "But there have been few demonstrations of complete digital systems using this exciting technology. Here is the proof."

CNTs are long chains of carbon atoms that are extremely efficient at conducting and controlling electricity. In addition, they're extremely thin--thousands of CNTs could fit side by side in a human hair. This means that it takes very little energy to switch them off.

"Think of it as stepping on a garden hose," said H.S. Philip Wong, one of the researchers, in a news release. "The thinner the hose, the easier it is to shut off the flow."

In fact, the combination of efficient conductivity and low-power switching make CNTs excellent candidates to serve as electronic transistors. Scientists even estimate that CNTs could take us at least an order of magnitude in performance beyond what silicon transistors could.

The main issue with silicon transistors is that they're getting smaller. Progress in electronics has meant shrinking the size of each transistor to pack more of them on a chip. As they become smaller, though, they waste more power and generate more heat in a smaller and smaller space. This means that, eventually, silicon-based systems will be limited by temperature.

Despite the potential for CNTs, though, there have been inherent imperfections that have halted their use. CNTs do not necessarily grow in neat parallel lines, as chipmakers would like. And while researchers have devised tricks to grow 99.5 percent of CNTs in straight lines, imperfections could still cause issues.

Now, though, researchers have found a way to deal with misaligned and/or metallic CNTs without having to hunt for them like needles in a haystack. The new two-pronged approach is called an "imperfection-immune design." It eliminates wire-like or metallic nanotubes and then bypasses the misaligned nanotubes. This allowed researchers to assemble a basic computer with 178 transistors, a limit imposed by the fact that they used their university's chip-making facilities rather than an industrial fabrication process.

The findings are important for taking the first steps toward taking carbon nanotubes from the lab and making them applicable in the real world. If CNTs can be used in computers and electronics, we may just see a revolution in these devices.

The findings are published in the journal Nature.