(February 20, 2012) In a remarkable feat of micro-engineering,
UNSW physicists have created a working transistor consisting of a single atom
placed precisely in a silicon crystal.
The tiny electronic device,
described today 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 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.