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Scanning Tunneling Microscopy: an Introduction Scanning Tunneling Microscopy (STM as it is known) is a powerful technique for imaging surfaces with extremely high resolution. Resolution refers to how small of a feature you can see. The technique of STM was invented in 1981 by two researchers in Zurich, Switzerland - Gerd Binnig and Heinrich Rohrer. In 1986, they were awarded a Nobel prize for their invention. To understand why their instrument was so good, you have to think about how people imaged surfaces before that time. Conventional microscopes, which are still in use today, use light and lenses to magnify a tiny piece of a surface so that one can see the small features. With stronger and stronger lenses, it is possible to see smaller and smaller features. However, there is a limit to how small you can get - namely, the wavelength of the light we see - which is about 600 nm (600 billionths of a meter). Features smaller than the wavelength of light cannot be seen. 600 nm may seem small to some people, but consider that the distance between atoms on a surface is only about 0.3 nm, 2000 times smaller than this. To image individual atoms, one needs a microscope which operates on an entirely different principle. This is where the STM comes into play.