Practical Electron Microscopy and Database

Electron energy loss spectroscopy (EELS) measures the spectral distribution of energy transferred from an incident electron beam into a specimen. In general, there are mainly two types of fundamental methods:
         i) Low energy beams reflected by solid surfaces, presenting the excitation spectrum from meV to eV. A representative technique is vibrational spectroscopy.
         ii) High energy beams transmitted through thin TEM films, presenting the inelastic scattering events in an energy range of eV to keV.

EELS is related to electronic, optical and mechanical properties of the observed materials. Methods i) and ii) above are also called reflection electron energy loss spectroscopy (REELS) and transmission electron energy loss spectroscopy (TEELS) modes, respectively. However, different from REELS, the name of TEELS is conventionally simplified as EELS.

Table 2331. Comparison between TEELS (EELS) and REELS.