June 3, 2005 – Canadian engineers have unveiled the creation of what they say is the world’s smallest transistor in which electricity flows through a molecule, reported the Agence France-Presse. The device is only visible through a powerful microscope, but experts say it may be the biggest development so far in nanotechnology.
“It’s a big step forward. It could never have been said before with certainty that a molecule could be a building block and now there’s no doubt,” Robert Wolkow, head of the research team at the University of Alberta told AFP. “It’s no longer science fiction. There is no question, molecules can be used as electronic components.”
The team’s results appeared in the scientific journal Nature yesterday.
Wolkow’s transistor, which consists of one to 20 molecules anchored to a silicon wafer, is nearly one thousand times smaller than conventional transistors and requires about one millionth as much energy.
An electrode or metal tip hovers above the molecule. When activated, “you can see a sloping effect, like a comet’s tail,” he said. “You can see the decay of the electric field from the charge.”
The breakthrough is the result of five years of intense work by Wolkow and his colleagues. It took that long just to figure out how to line up the molecules and the small electrodes and control the flow of electricity in repeated experiments at the National Institute for Nanotechnology in Edmonton.
But, consumers should not expect to see the technology in gadgets on store shelves anytime soon. There are still many bugs to work, Wolkow said.
First, the metal probe that is “ever so carefully poised over the molecule” is moved into position using a special microscope that costs about one million (800,000 US) dollars.
“Obviously, a transistor that requires a million-dollar microscope to work is impractical,” he said.
Also, it takes the team several minutes to turn it on or off. To be useful in a computer, it would need to make the switch in less than a microsecond, or one millionth of a second.
It is more likely the first applications for the device will be as a sensor or medical diagnostic tool that could trigger the release of drugs in specific locations in the human body or detect levels of iron or oxygen in the blood, Wolkow said.
“There’s a long way to go to making a molecular computer. That requires interconnecting millions of these entities and have them function collectively,” he said.