Energy efficiency at the atom level

Researchers at Armonk, N.Y.-based IBM (NYSE:IBM) announced they have used an atomic force microscope to look inside a molecule, representing some of the highest-resolution insight into the electronic and chemical properties of the world's smallest building blocks.

The findings could be used to understand and chart charge distribution at the atom level, offering potential applications in improving the energy efficiency of computing components and the conversion of solar energy to electricity, said Fabian Mohn, an IBM scientist, in an interview with the Cleantech Group today.

"The significance of the research is more in opening up possibilities for further research, not so much direct application," he said. "It's a new technique of investigating atomic or molecular systems."

The nanotechnology researchers at IBM's Zurich lab in Switzerland compared the findings to an x-ray that provides an image of bones and organs inside a human. Similarly, the non-contact atomic force microscopy shows the atomic structures of individual molecules, offering the opportunity to study the electronic and chemical properties. 

The imaging of the pentacene molecule was conducted in an ultrahigh vacuum at extremely low temperatures, around -268 degrees Celsius (-451 Fahrenheit). The scientists were able to look through the electron cloud to view the "atomic backbone" of the atom.

The work builds on a prior milestone that IBM announced in June. The atomic force microscope allowed researchers to measure the charge states of atoms, enabling them to determine how a single electron charges on an insulating surface. The tool could help them understand how charge transmits through molecules, which IBM says could help them build smaller, faster, more energy-efficient computing components.

"In semiconductor devices like chips, it's very important if you downscale the size to be able to determine the position of individual charges, and there I think this could come in handy," Mohn said. "Apart from that, charge transport is also important in devices that convert solar energy to a current."

Makers of computing hardware subscribe to the principle of Moore's law, in which the number of transistors that can be placed on an integrated circuit has doubled approximately every two years (see The REAL story on Moore's Law & solar). However, Intel's Gordon Moore, for whom the law is named, has said it cannot be sustained indefinitely.

IBM's findings could be used to get past that point.

"Silicon technologies will eventually meet a physical limit when they can't be down-scaled further," Mohn said. "Semiconductor technologies used now will have to be replaced, and one idea is using single molecules as transmitters."

Applying the findings to commercial products is 15 to 20 years away, he said, but the team published the breakthrough so other scientists and universities could take advantage of the techniques that allowed some of the most in-depth exploration of molecules so far. Mohn said IBM's atomic force microscope is unique because it has an oscillating tip and a quartz tuning fork that enables its specialties. Its highly sensitive, sharp tip measures the force between the tip and the molecule at a distance of less than a nanometer

IBM scientists, in collaboration with the University of Regensburg in Germany, were the first to measure the force it takes to move individual atoms on a surface, which could improve the design of computer chips and miniaturized storage devices (see Nanotech gets cleantech boost from IBM, Saudi Arabia). Researchers at IBM's lab in Almaden, Calif., who conducted those atomic force measurements are now working with the Nanotechnology Centre of Excellence in Saudi Arabia studying applications in solar energy, water desalination and recyclable materials.

See IBM's device to measure atomic force »

The newly announced research has already prompted interest from UK researchers who are studying bacteria from the deep sea, Mohn said. They contacted the IBM team about using the same techniques to find out structures of molecules extracted from the bacteria.

Mohn said the next step for the IBM team is to further develop the imaging mechanism in order to examine other molecules and distinguish different species of atoms.

In the long term, the team envisions building a molecular structure made of several molecules on insulating surfaces and investigating how charge transport occurs in a molecular network. Such research could take five years, depending on unexpected obstacles.

The team also included Leo Gross, Nikolaj Moll and Gerhard Meyer, in addition to Utrecht University's Peter Liljeroth.