Optimum experimental conditions for quantitative surface microanalysis by reflection electron energy-loss spectroscopy
Wang, Z. L. (Zhong Lin)
MetadataShow full item record
Experimental conditions for obtaining high quality core-shell ionization edges in reflection electron energy-loss spectroscopy (REELS) are investigated. Under the (600) specular- "mirror" reflection conditions and using the relative ionization cross-section measured from a MgO thin foil in the transmission geometry for collection semi-angle β = 1.2mrad, the chemical composition of MgO (100) surfaces is determined to be NO/NMg = 1.5 ± 0.15. This value is not significantly affected by varying the resonance diffraction conditions near the  zone axis, under which the spectra were acquired. An incorrect apparent composition will result if channeling effects along the  zone axis are not considered properly. Surface microanalysis is limited by the accuracy of the core-shell effective ionization cross-section (EICS), which depends not only on the property of a single atom but also on the dynamical elastic and inelastic scattering and channeling processes of electrons. An experimental method is outlined by which to measure the relative EICS from a thin foil specimen in the transmission case under the equivalent resonance conditions as in reflection geometry.