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July 16, 2006

Development of one atom thick coating should lead to far better microscopes

One atom thick coating for tooltips created. National Institute of Nanotechnology at the U of Alberta, used a unique process to make the sharpest tip ever known and opened the door to a range of possibilities. Technically speaking, they were able to coat peripheral atoms near the peak with nitrogen, making it a one atom-thick, tough protective paint job. "That coating has the effect of binding the little pyramid of metal atoms or Tungsten, in place," said Dr. Robert Wolkow, a physics professor at the U of A and co-author on the research paper published in the Journal of Chemical Physics. "Such a pointy pyramid of metal atoms would normally just smudge away spontaneously. It's like a sand pile--you know you can't make it arbitrarily pointy. If you try to pile on more sand, it flows down and makes a more blunt pile. Metal atoms will do the same thing."

These sharp tips are needed for making contact with metals or semiconductors as well as for the manipulation and examination of atoms, molecules and small particles. Ultrafine tips are demanded for future experiments where the results are directly dependent on shape of the tip.

The tips made by Wolkow and the research team--made up of Moh'd Rezeq and Jason Pitters from NINT--are so stable they withstand about 900 degrees Celsius. They are so sharp they appear so far to serve as excellent emitters of electron beams. "The lenses in an electron microscope work more perfectly if the electron beam comes from a really small point," said Wolkow. "Since we have the smallest point source of electrons, we think we will be able to make the best electron microscopes. This is speculation, but based on pretty conventional thinking.

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