World's first carbon nanotube computer built.

Norbert von der Groeben

World's first carbom nanotube computer built bye a team of Stanford engineers has built a basic computer using carbon nanotubes, a semiconductor material that has the potential to launch a new generation of electronic devices that run faster, while using less energy, than those made from silicon chips.

What is carbon nano tube..?

Carbon nanotubes (CNTs) are hollow cylinders composed of a single sheet of carbon atoms.They have exceptional properties which make them ideal as a semiconductor material for building transistors, the on-off switches at the heart of electronics.

For starters, CNTs are so thin - thousands could fit side-by-side in a human hair - that it takes very little energy to switch them off."Think of it as stepping on a garden hose. The thinner the pipe, the easier it is to shut off the flow," said HS Philip Wong, co-author on the study.But while single-nanotube transistors have been around for 15 years, no-one had ever put the jigsaw pieces together to make a useful computing deviceSo how did the Stanford team succeed where others failed? By overcoming two common bugbears which have bedevilled carbon computing.First, CNTs do not grow in neat, parallel lines. "When you try and line them up on a wafer, you get a bowl of noodles," says Mitra.

The Stanford team built chips with CNTs which are 99.5% aligned - and designed a clever algorithm to bypass the remaining 0.5% which are askew.They also eliminated a second type of imperfection - "metallic" CNTs - a small fraction of which always conduct electricity, instead of acting like semiconductors that can be switched off.To expunge these rogue elements, the team switched off all the "good" CNTs, then pumped the remaining "bad" ones full of electricity - until they vaporised. 

These are initial necessary steps in taking carbon nanotubes from the chemistry lab to a real environment," said Supratik Guha, director of physical sciences for IBM's Thomas J. Watson Research Center and a world leader in CNT research.

The Stanford research was supported in part by the National Science Foundation, SONIC, the Stanford Graduate Fellowship and the Hertz Foundation Fellowship.