Reflection electron microscopy and interferometry of atomic steps on gold and platinum single crystal surfaces

1992 ◽  
Vol 20 (4) ◽  
pp. 450-456 ◽  
Author(s):  
H. Banzhof ◽  
K. H. Herrmann ◽  
H. Lichte
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
Crystal Surfaces ◽  
Atomic Steps ◽  
Single Crystal Surfaces ◽  
Platinum Single Crystal ◽  
Reflection Electron Microscopy

Experiments on REM and SREM using a Tem/Stem Microscope with a Configurable Angle-Resolving Detector

1990 ◽  
Vol 48 (1) ◽  
pp. 338-339
Author(s):  
H. Banzhof ◽  
I. Daberkow
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
Crystal Surface ◽  
High Energy ◽  
Contrast Effects ◽  
Atomic Steps ◽  
Single Crystal Surfaces ◽  
Platinum Single Crystal ◽  
Reflection Electron Microscopy ◽  
Beam Reflection

A Philips EM 420 electron microscope equipped with a field emission gun and an external STEM unit was used to compare images of single crystal surfaces taken by conventional reflection electron microscopy (REM) and scanning reflection electron microscopy (SREM). In addition an angle-resolving detector system developed by Daberkow and Herrmann was used to record SREM images with the detector shape adjusted to different details of the convergent beam reflection high energy electron diffraction (CBRHEED) pattern.Platinum single crystal spheres with smooth facets, prepared by melting a thin Pt wire in an oxyhydrogen flame, served as objects. Fig. 1 gives a conventional REM image of a (111)Pt single crystal surface, while Fig. 2 shows a SREM record of the same area. Both images were taken with the (555) reflection near the azimuth. A comparison shows that the contrast effects of atomic steps are similar for both techniques, although the depth of focus of the SREM image is reduced as a result of the large illuminating aperture. But differences are observed at the lengthened images of small depressions and protrusions formed by atomic steps, which give a symmetrical contrast profile in the REM image, while an asymmetric black-white contrast is observed in the SREM micrograph. Furthermore the irregular structures which may be seen in the middle of Fig. 2 are not visible in the REM image, although it was taken after the SREM record.

Reflection Electron Microscopy

1975 ◽  
Vol 33 ◽  
pp. 122-123
Author(s):  
P. E. Højlund Nielsen ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
Chromatic Aberration ◽  
Dark Field ◽  
Energy Spread ◽  
Crystal Surfaces ◽  
Single Crystal Surfaces ◽  
Dark Field Imaging ◽  
Reflection Electron Microscopy ◽  
Field Imaging

Reflection electron microscopy was widely used before 1960 for the study of surfaces. For the imaging diffuse scattered electrons was applied. For avoiding a severe foreshortening the surface was illuminated and viewed at fairly large angles. That resulted in a large energy spread of the scattered electrons so the resolution was limited to about 500Å due to chromatic aberration. Since such a resolution could be achieved more readily in scanning microscopes, the method was abandoned. However for single crystal surfaces the situation is entirely different. If the surface can be maintained reasonably clean, strong diffraction spots can be obtained and the energy spread in the diffracted beam is usually small; thus the imaging of the surface can be performed in a manner similar to the dark field imaging of a thin crystalline specimen.

Sign in / Sign up

Export Citation Format

Share Document