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Scanning Tunneling Microscope
The incredible advance in microscopy of being able to see
objects as tiny as individual atoms was achieved by physicists
Heinrich Rohrer and Gerd Karl Binnig. The pair developed the
scanning tunneling microscope in 1981 while working for IBM
in Zurich, Switzerland.
Binnig was born in Frankfurt, Germany, on July 20, 1947.
He studied physics at J.W. Goethe University, where he completed
his bachelor's degree in 1973 and his doctoral degree in 1978.
That year he accepted a position with IBM's Research Laboratory
in Zurich, working with the physics research group.
Born in Buchs, Switzerland on June 6, 1933, Rohrer earned
his bachelor’s degree in physics from the Swiss Federal
Institute of Technology in Zurich in 1955 and his doctoral
degree in 1960. He traveled to the United States to do post-doctoral
research with Rutgers University and returned to Switzerland
in 1963 where he also joined IBM’s Zurich lab.
There the men met and began working together. It would be
more than a decade before their efforts would result in the
powerful breakthrough in research technology that they have
become famous for. The scanning tunneling microscope, or STM,
has the power to form an image of individual atoms on a metal
or semiconductor surface. The way it works is to scan the
tip of a needle, or “probe,” just a few atomic
diameters above the surface of the material. A voltage is
applied between the tip of the probe and the surface, and
as a current begins to flow between them, the STM can determine
minute variations in the distance electrons travel and save
this information in a data file. With this data the STM can
produce an image of the electrical topography of the surface.
In this way, the STM can “see” atomic-scale
objects up to 1/25th the diameter of a typical atom. By creating
three-dimensional profiles of a surface, the device can help
researchers in a variety of ways including determining size
and form of molecules, observing defects and abnormalities
on a surface, even discovering how chemicals interact with
a material. The STM quickly became standard equipment in laboratories
throughout the world, in fields as diverse as molecular biology,
metallurgy, chemistry and semiconductor science.
For their work, Binnig and Rohrer were honored with numerous
awards including the German Physics Prize, the Otto Klung
Prize, and the Hewlett Packard Prize, the King Faisal Prize.
In 1986, they were awarded the Nobel Prize in Physics along
with German scientist Ernst Ruska, who designed the first
In 1985, Binnig relocated to IBM's Almaden Research Center
in San Jose, California. There he and a team of researchers
invented the atomic force microscope, which allows scientists
to map non-electrically conducting surfaces as well. He was
a visiting professor at Stanford University from 1987 to 1988
and appointed an IBM Fellow in 1987. He continues to work
for IBM’s research arm.
Rohrer became an IBM Fellow in 1986 and managed the physical
sciences department at the Zurich Research Laboratory from
1986 to 1988. He retired from IBM in July 1997.