Scientists have created an exceptionally miniaturized transistor that uses a single atom. The breakthrough was made by physicists at the University of New South Wales, and the breakthrough is seen as a better foundation for scalable quantum computing. The transistor is composed of a single phosphorus-31 isotope that was precisely placed on the base of silicon using a Scanning Tunneling Microscope.
The isotope was placed on the silicon base inside an ultra-high vacuum chamber. Forbes reports that one of the amazing things about the breakthrough is that the physicists could position the individual phosphorus atom very precisely. The atom was confirmed to be exactly where it needed to be placed to be effective. The precision achieved through this technique is very important because the margin of error with most single atom devices is reportedly 10nm, which is large considering the minuscule scale when talking about atoms.
The team chose phosphorus-31 because it has two possible nuclear spins and has been theorized to be an ideal basis for solid-state quantum computing. Another important aspect of choosing phosphorus and silicon is that it would be conceivable that a processor based on this technique would be compatible with CMOS sensors in use today. A lot of work remains before a processor can be built using this technology. One big roadblock is that the technology used to build this transistor is very expensive. We are likely many years away from a working computer using single atom transistors.