Originally posted by another user
The transistor in question is a single phosphorous atom, etched into a silicon bed with "gates" to control electrical flow and metallic contacts to apply voltage. The reason this transistor is special? Because the process of making it is repeatable, which should mean that in the future it can be turned into a commercial reality. The research is reported in the journal Nature Nanotechnology.
Other scientists are impressed, too. "It's an absolutely fantastic piece of engineering," physicist Bruce Kane from the University of Maryland, who isn't involved with the work, told New Scientist. Its tiny size could see the development of processors we can currently only dream of.
As ever with these kinds of technological advances, though, there is a snag. In this case, it's the fact that the atom must be kept at -391 degrees Fahrenheit to keep it from migrating from where it's placed. However you cool your computer, it's fair to say that it won't be able to satisfy those kinds of conditions.
So it's a proof of concept, and no doubt about it. But the idea of consistently isolating a single atom to use as a transistor was lunacy a decade ago. Who knows what another ten years can bring?