Soldering Carbon Nanotubes (Part Two)

(continued from Part One)

Nonetheless, researchers have developed a way to solder carbon nanotubes. Carbon nanotubes are especially electrically conductive, but that doesn’t mean they’re superconductive as well. When current passes through a carbon nanotube, energy is lost as heat and this in turn causes a temperature gradient in the surrounding area.

Researchers have found a way to control the chemical reactions that occur at certain temperatures by limiting them to specific hot spots, causing small amounts of metal are deposited in these hot spots — amounts just large enough to solder nanotube junctions together.

This technique, known as chemical vapor deposition, is already widely used by the majority of manufacturing companies, meaning these manufacturers could integrate this process with existing technology in the future, thus severely curtailing the cost of replacing existing infrastructure. Let’s take a quick look at the carbon nanotube self-soldering process and the soldering equipment used, which lasts a few fleeting seconds, but which dramatically improves device performance.

The carbon nanotube array is arranged with horizontal tubes over vertical tubes inside a chamber of filled metal in gaseous form. Because of the nanotubes’ internal resistivity to electron flow, they heat more readily at the junctions. The junctions are soldered when the surrounding gas molecules react to the heat and depose on the hot spots. Afterward, the resistance drops, cooling the junction and essentially ending the reaction.

Soon we should see more manufacturers replacing silicon with carbon nanotubes, which will mark a major shift in technology.


George Leger has a Masters in Electrical Engineering from Stanford University, worked in private industry pioneering surface-mount technology and in government research labs for twenty years, published several papers on surface-mount technology, co-authored papers published in national symposiums on accelerator technology, was past president of SMTA and an adjunct professor at the community college level, holds a patent, and is a certified microchip design partner, serving as a consultant to many companies developing electronic circuits.

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