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Do Carbon Nanotubes Need To Be Doped As Silicon Is?

Carbon nanotubes have the potential to be used for smaller and faster computer chips, but static electricity poses serious problems with nanoscale elements in a circuit.

Static electricity has long been a problem for conventional chips and electronic devices, but it’s especially severe for nanotubes because of their extreme shape -- nanotubes are often micrometers long and only a few billionths of a meter in diameter.

A small zap of static electricity destabilizes the nanotubes, making them useless as a semiconductor.

To find out how severe the problem is, Pawel Keblinski, assistant professor of materials science and engineering at Rensellaer Polytechnic Institute (RPI), and Saroj Nayak, assistant professor of physics, combined quantum mechanics in theoretical computer simulations with classical electrostatics analysis.

They found that the electrostatic charge is concentrated at the tube ends. The charge eventually destroys the entire nanotube.

The researchers then calculated the maximum charge the tube can adopt before its ends become unstable. Besides providing a guide to “safe” operational conditions for nanotubes, this so-called “tube charging” technique could be used to open nanotube ends without damaging them.

This allows carbon atoms to react directly with other elements, such as oxygen, boron, and nitrogen.

Since carbon nanotubes in their purest form may not be the answer to building smaller, more efficient computer chips, the addition of elements such as nitrogen could provide new electrical characteristics to the tubes or could be used to increase the bonding between the tubes and other materials.

“It was exactly the same way with silicon technology. Silicon is not very useful in pure form. Other elements have to be added to provide proper electrical characteristics,” Keblinski says.

[Contact: Pawel Keblinski]






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