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The carbon computer

Carbon nanotubes — each skinnier than a strand of DNA — have been engineered into semiconductors that release less heat than those made from silicon. Because heat limits the size and speed of a chip, carbon nanotube semiconductors could lead to smaller, faster computers.

Carbon nanotubes as semiconductors. Illustration by Patterson Clark

Engineers overcame several hurdles to producing the semiconductors:

A semiconductor must be able to switch on and off, using a transistor. Defective tubes caused problems because they were always on.

Engineers found that they could switch off the properly working tubes, then overheat the defective ones, vaporizing them into carbon dioxide.

Some tubes could become misaligned, shorting out other circuits. Engineers developed algorithms to circumvent the misplaced signals.



Electrical current

Vaporized tube

Misaligned tube

SOURCE: Stanford University. Published Sept. 26, 2013.