reflection electron microscopy abbr., REM (rus. микроскопия, электронная отражательная abbr., ОЭМ) — a branch of microscopy that uses scattered high-energy electrons falling on a surface at glancing angles to generate an image of the surface.

Description

If a specimen is placed in an ultra-high vacuum environment, reflection microscopy can be used to observe processes occurring on the specimen’s surface. This technique enables one to observe atomic phases and regions of different reconstruction with the help of diffractive contrast.

Elastically scattered electrons form a diffraction pattern on the rear focal plane of an objective lens, where one or more diffraction reflections are eliminated by an aperture diaphragm. A magnified image is projected on the screen of the microscope.

One of the reflection electron microscope’s characteristic features, namely the difference in magnification in various directions along the specimen’s plane, is due to the tilt of the specimen in relation to the microscope’s optical axis.

Hence, this type of microscope usually has two magnification characteristics: magnification in the electron beam incidence plane and magnification in the plane perpendicular to the incidence plane.

As a result of this perspective imaging, only the central part of the image is in focus, while the upper and lower parts of the image are excessively and inadequately focused, respectively. Another effect of perspective image is a lower resolution along the direction of the electron beam.

Reflection electron microscopes have demonstrated resolutions of approximately 100 Å.

Authors

  • Veresov Alexander G.
  • Saranin Alexander A.

Sources

  1. Handbook of microscopy for nanotechnology / Ed. by Nan Yao, Zhong LinWang. — Kluwer Academic Publishers, 2005. — 731 p.
  2. Oura K. et al. Surface Science: An Introduction // Springer, 2010 - 452 pp.

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