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Think Thin

Researchers at the U. S. Department of Energy's Ames Laboratory and Iowa State University [profile] have found an unusual growth mode -- never before observed -- that may prove critical in developing atomic structures of unusual uniformity for nanotechnology applications.

The new frontier of nanotechnology deals with thin films, fine particles or chemical syntheses that can be measured in nanometers, or one-billionth of a meter. Such a minute scale means that the thinner you can make the film, the smaller you can make components such as switches, lasing materials and semiconductors. And packing more into a computer chip helps it to run faster.

The findings at the Ames Laboratory may allow the further miniaturization of silicon-based electronic devices, a major undertaking in light of the silicon industry's huge role in technological innovation and production.

Typically, when materials "grow" on a silicon film, the deposited metal atoms stack up in "islands" of widely varying height. Using scanning tunneling microscopy and quantitative electron diffraction, Ames Lab researchers, led by physicist Michael C. Tringides, have discovered that lead (Pb) atoms seem to be "intelligent" and make only one height choice, depending on the temperature (185 Kelvin to 220 Kelvin).

This ability to achieve exact control of layer thickness and atomic uniformity of thin films and nanostructures, according to Tringides, is the "Holy Grail of nanotechnology."

The fundamental research effort, supported by the Department of Energy s Office of Basic Energy Sciences, is providing significant information about the microscopic processes that control the growth of custom-made materials.

For more information, contact Tringides at (515) 294-6439, or Saren Johnston, Ames Laboratory Public Affairs.