Single-Atom Transistor: Why Small Is a Big Deal

A tiny achievement with huge significance was reported today by physicists at the University of New South Wales (UNSW). They have created a transistor that uses a single atom. Their work is described in a paper and an editorial published in the February 19 issue of Nature Nanotechnology.

Using a scanning tunneling microscope—the essential tool in nanotechnology that allows researchers to visualize and manipulate single atoms—the UNSW group positioned a phosphorous atom between nano-scale electrodes. A video explaining the feat is available.

CAPTION:This is a single-atom transistor: 3D perspective scanning tunnelling microscope image of a hydrogenated silicon surface. Phosphorus will incorporate in the red shaded regions selectively desorbed with a STM tip to form electrical leads for a single phosphorus atom patterned precisely in the center. Credit: ARC Centre for Quantum Computation and Communication, at UNSW.

What seems to be most important about this achievement is the accuracy of the placement of the phosphorous atom. This opens the possibility that precisely placed atoms may be used to create a whole new generation of computer chips that are both reliable and smaller than anything used today.

"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," said lead author Dr Martin Fuechsle in a press release from UNSW.

The leader of the research group, Professor Michelle Simmons, claims that "This is the first time anyone has shown control of a single atom in a substrate with this level of precise accuracy." Simmons is director of the ARC Centre for Quantum Computation and Communication at UNSW.

According to the famous “Moore’s Law,” which argues from past achievement in chip design and predicts future a doubling in chip power ever 18 months, single atom or quantum computing should be achieved by the year 2020. Fuechsle and Simmons are speculating that because of this breakthrough, technology is ahead of schedule.

If so, then arguments advanced by futurists such as Ray Kurzweil take on added significance. As chips grow in power and shrink is size, more and more powerful computing becomes possible. Smaller chips are more implantable, bringing us closer to they day when they are implanted not just for medical but for other purposes (see previous post).

Even more significant is that smaller and more powerful processing paves the way for more highly intelligent machines. Kurzweil predicts that within a few decades, machines with greater than human intelligence will be produced. What then? Will our inventions become the inventors of the future, and will they still need us? The report, "A Single-Atom Transistor," is published in the February 19 is of Nature Nanotechnology.