Sharpest microscope tip lands researcher a world record

(Edmonton) A very tiny, very sharp object has put Canadian researchers at the National Institute for Nanotechnology and the University of Alberta into the Guinness Book of World Records.

The team, made up of Robert Wolkow, NINT principal investigator, and physics professor Jason Pitters, research council officer at NINT and Mohamed Rezeq, formerly of NINT, created a tip used in electron microscopes that is just one atom wide at its end point.

Wolkow says the tip is like a light bulb, but it emits electrons, or ions, instead of light. A source of electrons, used in a scanning electron microscope, can be used to illuminate everything from cells to semiconductor chips, while a scanning ion microscope will be able to greatly clarify samples that are too small to generate much useful information.

"Those imaging advantages come about because our new source of ions is really, really small. It is like we have a light bulb the size of one atom," said Wolkow. "And, it turns out that an ion beam emanating from a single atom has great advantages in terms of image resolution and depth of field and contrast."

"We did not start out to set a world record; we were trying to make a better tool for our research," said Wolkow. "Having a world record is a fun achievement, but we are really interested in commercializing this product."

Wolkow says the NINT nanotip looks like an ordinary needle, unless you look closer trying to see the very end of it. He explains that with ever-more powerful microscopes, you would eventually find that the point terminates in a single atom that stands above all the others.

"An ordinary needle would look more like a very rough blob-with a relatively huge overall radius of curvature-composed of many uncountable atoms," he said. "You might imagine dumping a big box full of Lego blocks to form amorphous piles-and contrast that with a perfect pyramid of blocks-carefully assembled and stacked to form a point with only one little block at the top."

The tip is made of tungsten and fabricated using a patented controlled etching method. It is currently being evaluated for potential uses.

Wolkow says the same tip is now the source in a new holographic electron microscope built over the last couple of years at NINT. "We think it will reveal features of molecules and other nano-entities that can't be observed in any other kind of microscope," he said.

And although a world record was the last thing on the minds of the research team, Wolkow says he takes a bit of pride knowing that the record is here to stay.

"Unlike some world records, the atomic sharpness of the tip means that the record can't ever be broken-one can't get sharper," he said.