Flawed nanotubes could be perfect silicon replacement
The paradox of perfection – that flaws make things perfect – could be the key to designing nanoelectronic circuits from carbon nanotubes, according to US scientists.
They have discovered that a circuit of nanotubes can only guide a current if some of the tubes carry structural defects.
Individual carbon nanotubes are exceptionally good conductors because they are essentially a single carbon molecule. They can even outdo silicon at transmitting charge, which means nanotube circuits could boost computing speeds while reducing chip size (see our feature What happens when silicon can shrink no more? ).
But connecting nanotubes into such circuits is not easy, says Vincent Meunier at Oak Ridge National Laboratory in Tennessee. "The connections between individual nanotubes do not conduct well," he says.
Instead of jumping easily into an adjacent nanotube, as they would between metal wires, electrons are more likely to bounce back when they reach the end of a tube, says Meunier. Electrons treat junctions between nanotubes as barriers – what scientists call "opaque".