Elemental analysis by x-ray and electron energy-loss spectroscopy

Abstract

The inner-shell ionization of atoms results in an emission of characteristic x-ray quanta or Auger electrons. A wavelength- or an energy-dispersive x-ray spectrometer can be coupled to a transmission electron microscope to record x-ray quanta emitted from the specimen. The quantitative methods developed for the x-ray microanalysis of bulk materials can be transferred to the investigation of thin specimens. Electron energy-loss spectroscopy (EELS) gives information about the electronic structure and the elemental composition of the specimen. This technique is more efficient than x-ray analysis for low-Z elements because the spectrometer can collect a large fraction of the inelastically scattered electrons, which are concentrated within small scattering angles. By deconvolution and background subtraction, a net signal can be obtained from the ionization edge of an element for subsequent quantitative analysis. An imaging electron-energy filter makes it possible to work in the electron spectroscopic imaging modes, which can be used for mapping the elemental distribution. © 2008 Springer Science+Business Media, LLC All rights reserved.