Materials Characterisation using Electron Beams

  Book page with a representation of the signals excited in a sample by electron beams Copyright: © Thomas Weirich

When fast, high-energy electrons strike solid matter, they are able to penetrate into the solid body or penetrate thin samples according to their kinetic energy. Interaction with the electric fields of the atoms at different depths of the material alters the direction of electron movement of the primary electrons and yields to energy losses. For compact solid bodies most of the primary beam electrons loose all their kinetic energy in these interactions and become absorbed in the solid.

 
 

Interaction

View of the console and monitor of a scanning electron microscope during an examination. Copyright: © GFE

The interaction between beam electrons and the atoms in the solid under investigation triggers a number of different phenomena, most of which can be used as signals in analytical electron microscopy:

  • Backscattering of beam electrons by SEM
  • Emission of secondary electrons by SEM
  • Excitation and emission of characteristic X-rays using WDX, EDX and EELS.
  • Interference effects in solids with ordered internal structure using EBSD and TEM.
 
Abbreviation Meaning
SEM Scanning Electron Microscop
WDX Wavelength Dispersive Analysis of X-Rays
EDX Energy Dispersive X-Ray Analysis
EELS Electron Energy Loss Spectrometry
EBSD Electron Backscatter Diffraction
TEM Transmission Electron Microscop