the phrase, "sharp as a tack." Now, thanks to new
University of Alberta research the popular expression
might become, "sharp as a single atom tip formed
by chemically assisted spatially controlled field
evaporation." Maybe it doesn't roll off the tongue
as easily, but considering the researchers have created
the sharpest object ever made, it would be accurate.
scientists, working out of the National Research
Council's National Institute of Nanotechnology
at the U of A, 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.
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.
this works, and it remains to be proven, it would
be like taking a modest car and making it go like
a race car by just changing its spark plugs. We
would take a conventional electron microscope,
put in one of our tips as the electron source and
render the microscope instantly improved and capable
of finer resolution."
Electron microscopes enable advances in diverse
areas. Research problems that are just out of reach
today but that could be made accessible by advances
in electron microscopy include studies of the little
pores that form in our cells walls and which are
centrally important in the regulation of all life
processes as well as new nano-structured materials
that are ultra-light yet strong, allowing reduced
energy consumption in vehicles.
Wolkow also expects their sharp tips will allow
electrical characterization of extremely small objects,
in turn allowing new device concepts to be discovered
For more information, please contact:
Dr. Robert Wolkow, Faculty of Science
University of Alberta, (780)492-8980