Peter Emerson

What are Scanning Tunneling Microscopes?

The scanning tunneling microscope is used extensively to discover the topography of tiny particles.  The scanning tunneling microscope produces a three dimensional replication of the object under study by creating a beam of electrons that is scanned over the surface of the subject.

The electrons bounce back and forth between the subject and the beam creating a three dimensional picture of the subject.  It is important to note that a scanning tunneling microscope performs a similar function to a scanning electron microscope, but they are not the same thing. 

Heinrich Rohrer and Gerd Binnig invented the scanning tunneling microscope in 1981 at the IBM lab in Zurich, Switzerland.  They won a Nobel Prize for Physics for their invention in 1986.  The scanning tunneling microscope, also known as STM, allows scientists to view and move the individual atoms of a sample.   

Scanning tunneling microscopes are used in research and industrial settings to study the atomic level surfaces of different materials.  The STM operates by creating an electron field a very short distance from the object being studied.  The electron cloud is created with a very sharp needle tip, often small enough to have room for only a single atom.  The needle tip then scans over the subject at a very close distance.  The distance between the needle and the surface of the subject affects the interaction of the electrons, giving viewers an atomic level three-dimensional picture of the subject’s surface.  The STM creates a type of topographic map of the subject’s surface, showing every atom-sized bump and crevice.  

The STM can manipulate individual atoms by creating chemical reactions.  The STM can remove and add electrons to atoms, thus altering their chemical structure.

Scanning tunneling microscopes are precise tools used by scientists and researchers to examine molecules that are invisible to the naked eye.  Without the scanning tunneling microscope, it would be impossible to fully understand the workings of matter at the atomic level.

Article Tags: Scanning Tunneling, Atomic Level

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