KIT Physicists Develop World’s Smallest, Single-Atom Transistor

Karlsruhe (KIT) physicists have developed the world’s smallest transistor using a single atom.

Led by physicist Professor Thomas Schimmel, the researchers have created a device that switches an electric current via the controlled displacement of a single atom.

According to the researchers, the single-atom transistor is capable of functioning at room temperature and has proven to consume very less energy.

Transistors are central to digital data processers. Modern day electronics contain no less than a billion transistors today. This also makes them responsible for 10 percent of electricity consumption.

The single-atom transistor is thus being viewed as a forerunner that could contribute significantly to energy efficiency in Information Technology (IT) in the future:

“Switching energies are possible with this quantum electronic element. which is a factor of 10 000 below those of conventional silicon technologies, “says Schimmel.

The Karlsruhe team has made a presentation of their miniature transistor in the magazine Advanced Materials. They were successful in making two tiny metal contacts between which there is a gap in the width of a single metal atom.

“Via an electrical control pulse, we push a single silver atom into this gap – the circuit is closed,” explains Schimmel. “If we push the silver atom out again, the circuit is interrupted.”

Unlike conventional quantum electronic devices. however, the single-atom transistor does not work until it reaches extremely low temperatures near the absolute temperature zero of minus 273 degrees Celsius.

The Karlsruhe single-atom transistor has so far depended on a liquid electrolyte. Schimmel and his team have now for the first time produced a transistor that works in a solid electrolyte.

According to the researchers, the gel electrolyte formed by gelling an aqueous silver electrolyte with fumed silica combines the advantages of a solid with the electrochemical properties of a liquid, thus improving both safety and security of the single-atom transistor.