A scanning tunneling microscope that operates at high pressures and high temperatures (430 K) and during catalytic reactions

1992 ◽  
Vol 14 (3-4) ◽  
pp. 263-269 ◽  
Author(s):  
B. J. McIntyre ◽  
M. B. Salmeron ◽  
G. A. Somorjai
1996 ◽  
Vol 466 ◽  
Author(s):  
M. Umekawa ◽  
S. Ohara ◽  
S. Tatsukawa ◽  
H. Kuriyama ◽  
S. Matsumoto

ABSTRACTThe formation of the boron-induced reconstruction on Si(111) 7×7 surface has been studied with scanning tunneling microscope. By evaporating elemental B on Si elevated at high temperatures, reconstructed structures develop from the step edge to the adjacent lower terrace. They emerge at temperatures between 800°C and 900°C. It indicates that phase transition from 7×7 to 1×1 surface structure is necessary for forming the √3-B reconstructed structures. The phase boundary between 7×7 and regions is a straight line with termination of the faulted halves of 7×7 unit cell. It is also found that strip or triangle regions are formed, depending on the direction of the step propagation.


Author(s):  
Rebecca W. Keller ◽  
Carlos Bustamante ◽  
David Bear

Under ideal conditions, the Scanning Tunneling Microscope (STM) can create atomic resolution images of different kinds of samples. The STM can also be operated in a variety of non-vacuum environments. Because of its potentially high resolution and flexibility of operation, it is now being applied to image biological systems. Several groups have communicated the imaging of double and single stranded DNA.However, reproducibility is still the main problem with most STM results on biological samples. One source of irreproducibility is unreliable sample preparation techniques. Traditional deposition methods used in electron microscopy, such as glow discharge and spreading techniques, do not appear to work with STM. It seems that these techniques do not fix the biological sample strongly enough to the substrate surface. There is now evidence that there are strong forces between the STM tip and the sample and, unless the sample is strongly bound to the surface, it can be swept aside by the tip.


Author(s):  
J. T. Woodward ◽  
J. A. N. Zasadzinski

The Scanning Tunneling Microscope (STM) offers exciting new ways of imaging surfaces of biological or organic materials with resolution to the sub-molecular scale. Rigid, conductive surfaces can readily be imaged with the STM with atomic resolution. Unfortunately, organic surfaces are neither sufficiently conductive or rigid enough to be examined directly with the STM. At present, nonconductive surfaces can be examined in two ways: 1) Using the AFM, which measures the deflection of a weak spring as it is dragged across the surface, or 2) coating or replicating non-conductive surfaces with metal layers so as to make them conductive, then imaging with the STM. However, we have found that the conventional freeze-fracture technique, while extremely useful for imaging bulk organic materials with STM, must be modified considerably for optimal use in the STM.


Author(s):  
Jean-Paul Revel

The last few years have been marked by a series of remarkable developments in microscopy. Perhaps the most amazing of these is the growth of microscopies which use devices where the place of the lens has been taken by probes, which record information about the sample and display it in a spatial from the point of view of the context. From the point of view of the biologist one of the most promising of these microscopies without lenses is the scanned force microscope, aka atomic force microscope.This instrument was invented by Binnig, Quate and Gerber and is a close relative of the scanning tunneling microscope. Today's AFMs consist of a cantilever which bears a sharp point at its end. Often this is a silicon nitride pyramid, but there are many variations, the object of which is to make the tip sharper. A laser beam is directed at the back of the cantilever and is reflected into a split, or quadrant photodiode.


1988 ◽  
Vol 49 (C6) ◽  
pp. C6-55-C6-59 ◽  
Author(s):  
O. NISHIKAWA ◽  
K. HATTORI ◽  
F. KATSUKI ◽  
M. TOMITORI

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