‘Quantum dot’ promises faster PCs

Scientists have created a transistor in a computer chip that is 10 times smaller than those commonly in use now, marking the start of a new age of super-fast, super-powerful computing.

At the heart of the electronic device is a “quantum dot”, which measures just four-billionths of a metre – so small that it contains just seven atoms, compared to the millions that make up a typical laptop chip.

The technical breakthrough is reported today in the journal Nature Nanotechnology.

The paper’s co-author, Michelle Simmons, said the achievement marked the first time scientists had been able to dictate the placement and behaviour of single atoms within a transistor.

“We’re basically controlling nature at the atomic scale,” she said. “This is one of the key milestones in building a quantum computer.”

Professor Simmons, director of the University of New South Wales centre of excellence for quantum computer technology, said devices made at this scale would allow more complex computations at exponentially greater speeds. This would also improve database searching and eventually lead to “100 percent secure communication”.

“It has many implications for national security and for the financial system and transferring information of any kind,” she said.

This single-crystal dot, Professor Simmons said, was proof that it was possible to build the ultimate computer – a quantum computer in silicon.

The atoms of the quantum dot are embedded in one silicon crystal.

Professor Simmons said the team chose silicon because of its longer lifespan and because it would be compatible with existing technology.

“All our computers contain silicon chips,” she said. “Building transistors at the atomic-scale means that anything electrical like computers and mobile phones will get smaller and faster while their functionality increases dramatically.”

The team’s goal is to develop a single-atom transistor – unthinkable in 1949, when the first computer commissioned in Australia took up a whole room.

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