How it began
Gerd Binnig and Heinrich Rohrer worked at the IBM Zurich Research Laboratory in Switzerland in the late 1970s. Both had backgrounds in superconductivity, were interested in the surfaces of materials and were frustrated by the lack of tools for studying them. They submitted their first patent disclosure in January 1979 and then, with the help of fellow researcher Christoph Gerber, designed and built the instrument over 27 months. Binnig recalled first seeing results on the night of March 16, 1981.
Before it existed
The optical microscope cannot resolve objects smaller than a wavelength of light. The electron microscope images very small objects with electron beams, but not at the level of individual atoms on a surface. Binnig and Rohrer built on the work of Russell D. Young of the United States National Bureau of Standards, who in the 1960s and early 1970s had combined a tunneling current with a scanning device to study metal surfaces.
How it works
The tip of a tungsten needle, a single atom wide at its point, is scanned a few angstroms above the surface of a sample. A small electric current tunnels across the gap between tip and surface, and its strength varies with the shape of the surface. These variations are measured and turned into an image like a three-dimensional relief map. Making it work required reducing vibration and noise and controlling the position, movement and sharpness of the tip very precisely.
What changed first
The first experiment examined the surface of a gold crystal and showed a landscape 100 angstroms square with a spatial resolution not achieved before. The instrument was announced in 1981. Its largest early effect was in semiconductors, where knowledge of materials at the atomic level supported the miniaturization of chips. In 1986 Binnig and Rohrer received the Nobel Prize in Physics.
What lasted
The microscope proved able to move atoms as well as image them. In 1990 the IBM scientists Donald Eigler and Erhard Schweizer used one to arrange xenon atoms to spell I-B-M. It is widely credited with giving rise to the field of nanotechnology and is used in semiconductor manufacturing, molecular biology and materials science. In 2011 IBM opened the Binnig and Rohrer Nanotechnology Center in Rüschlikon, Switzerland.
