Scientists can now create single-atom transistors repeatedly

21 February 2012 University of New South Wales (UNSW) physicists have created a working transistor consisting of a single atom placed precisely in a silicon crystal. The tiny electronic device, described in a paper published in the journal Nature Nanotechnology,…

21 February 2012

University of New South Wales (UNSW) physicists have created a working transistor consisting of a single atom placed precisely in a silicon crystal. The tiny electronic device, described in a paper published in the journal Nature Nanotechnology, uses as its active component an individual phosphorus atom patterned between atomic-scale electrodes and electrostatic control gates.


This unprecedented atomic accuracy may yield the elementary building block for a future quantum computer with unparalleled computational efficiency.Until now, single-atom transistors have been realised only by chance, where researchers either have had to search through many devices or tune multi-atom devices to isolate one that works.

“But this device is perfect”, says Professor Michelle Simmons, group leader and director of the ARC Centre for Quantum Computation and Communication Technology at UNSW. “This is the first time anyone has shown control of a single atom in a substrate with this level of precise accuracy.”

The microscopic device even has tiny visible markers etched onto its surface so researchers can connect metal contacts and apply a voltage, says research fellow and lead author Dr Martin Fuechsle from UNSW.

“Our group has proved that it is really possible to position one phosphorus atom in a silicon environment – exactly as we need it – with near-atomic precision, and at the same time register gates,” he says.

According to Dr Fuechsle, the device’s electronic characteristics exactly match theoretical predictions undertaken with Professor Gerhard Klimeck’s group at Purdue University in the US and Professor Hollenberg’s group at the University of Melbourne, the joint authors on the paper.