Microscope Looks At Atomic World

Oak Ridge National Laboratory researchers are peering into the atomic world with record clarity, developing an electron microscope image that can distinguish the individual, dumbbell-shaped atoms of a silicon crystal.

"Every time you see something more clearly you learn some secrets," said Stephen Pennycook, who heads the lab's electron microscopy group.

In a Sept. 17 article in the journal Science, Pennycook and colleagues wrote that they have achieved an image resolution at 0.6 angstrom, breaking the previous record of 0.7 angstrom which the lab set earlier this year.

An angstrom, the smallest wavelength of light, is about 500,000 times smaller than the thickness of a human hair.

Researchers say being able to see how materials bond together at an atomic level could prove a significant benefit to the semiconductor industry, chemistry and in the development of new materials.

For its latest findings, the Oak Ridge lab used a 300-kilovolt state-of-the-art electron microscope aided by new computerized imaging technology developed by Nion Co. of Kirkland, Wash.

The technology, called aberration correction, fixes imperfections on the microscope's electron lenses.

"We are crossing that threshold where we can really see atoms clearly for the first time ever," Pennycook said.

Pennycook compared the resolution correction technology to being able to focus 50 lenses simultaneously.

"That is what makes it really quite a historic achievement because it has been attempted for the last 50 years actually, and only in the last few years has it really proved feasible," he said.

Five years ago the Oak Ridge lab set a world record with a resolution at 1.3 angstrom without the aberration technology. Researchers said the next frontier will be seeing atoms in three dimensions.

By Duncan Mansfield