[LINK] Nano-transistor breakthrough to offer billion times faster computer

David Boxall david.boxall at hunterlink.net.au
Mon Feb 20 12:19:06 AEDT 2012


Deborah Smith
February 20, 2012

SYDNEY scientists have built the world's tiniest transistor by precisely 
positioning a single phosphorus atom in a silicon crystal.

The nano device is an important step in the development of quantum 
computers – super-powerful devices that will use the weird quantum 
properties of atoms to perform calculations billions of times faster 
than today's computers.

Michelle Simmons, of the University of NSW, said single atom devices had 
only been made before by chance and their margin of error for placement 
of the atom was about 10 nanometres, which affected performance.

Her team was the first to be able to manipulate individual atoms with 
"exquisite precision".

Using a technique involving a scanning tunnelling microscope, they were 
able to replace one silicon atom from a group of six with one phosphorus 
atom, achieving a placement accuracy of better than half a nanometre. 
"This device is perfect," Professor Simmons, director of the Australian 
Centre of Excellence for Quantum Computation and Communication 
Technology, said.

The single atom sits between two pairs of electrodes, one about 20 
nanometres apart, the other about 100 nanometres apart.

When voltages were applied across the electrodes, the nano device worked 
like a transistor, a device that can amplify and switch electronic signals.

The research is published today in the journal Nature Nanotechnology.

First developed in the 1950s, transistors revolutionised the electronics 

Since then, miniaturisation has seen the number of transistors squeezed 
onto a circuit double about every two years – a trend known as Moore's law.

Professor Simmons said this led to the prediction that transistors would 
need to reach the single atom level by 2020.

"So we decided 10 years ago to start this program to try and make single 
atom devices as fast as we could, and try and beat that law."

This had now been achieved eight to ten years ahead of the industry's 
schedule, she said.

Last year, Professor Simmons was named NSW Scientist of the Year for her 
team's research.

About 15 to 20 years of research is needed before quantum computers 
become widely available.

Researchers at Purdue University in the US, the University of Melbourne 
and the Korea Institute of Science and Technology Information in Daejeon 
were also involved in the research.

David Boxall                    |  When a distinguished but elderly
                                |  scientist states that something is
http://david.boxall.id.au       |  possible, he is almost certainly
                                |  right. When he states that
                                |  something is impossible, he is
                                |  very probably wrong.
                                                  --Arthur C. Clarke

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