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Scanning Tunneling Microscopy: A Surface Structural Tool Shirley Chiang Robert J. Wilson IBM Almaden Research Center San Jose, Calif. 95120
The scanning tunneling microscope (STM) is a new tool for measuring surface topography on a subatomic scale. The instrument has been used to make three-dimensional, real-space images of solid surfaces with vertical resolution as high as 0.01 A and horizontal resolution as high as ~ 2 Â. Scanning tunneling microscopy was developed by G. Binnig, H. Rohrer, Ch. Gerber, and E. Weibel at the IBM Zurich Research Laboratory in 1982. Their work attracted attention because it provided for the first time a method of measuring the structure of solid surfaces in three-dimensional real space with atomic resolution. In their early work, the technique was applied to such diverse systems as the S i ( l l l ) 7 X 7 reconstruction, reconstructed Au(110) and Au(100) surfaces, and chemisorbed oxygen atoms on Ni(110) and Ni(100). Binnig and Rohrer were awarded half of the 1986 Nobel Prize in physics for their achievements (1). Since the time of Binnig and Rohrer's pioneering work, the field of scanning tunneling microscopy has grown rapidly; many groups have built new instruments and applied them to various problems. Early practitioners of the art included teams headed by R. M. Feenstra at the IBM T. J. Watson Research Center (Yorktown Heights), C. F. Quate at Stanford University, J. A. Golovchenko at Bell Laboratories, and N. Garcia at Universidad Autonoma (Madrid). The popularity of this technique has grown substantially in a short period of time. In 1985 approximately 35 people attended a workshop on scanning tunneling microscopy held in Oberlech, Austria, under the auspices of the IBM Europe Institute. Several of the parti0003-2700/87/A359-1267/$01.50/0 © 1987 American Chemical Society
cipants displayed beautiful atomic resolution images of surfaces; others were heavily involved in the instrumentbuilding stage. Only two years later, the 2nd International Conference on Scanning Tunneling Microscopy/Spectroscopy (STM '87) attracted more than 300 people, and high-resolution
surface microscopy seemed routine. The instrument has now been applied successfully to such diverse problems as metal surface reconstruction in the presence of chemisorbed molecules (R. J. Behm and co-workers, University of Munich), spectroscopy of electronic states of metals on semiconduc-
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