Electron inelastic mean free path for Ti, TiC, TiN and TiO2 as determined by quantitative reflection electron energy-loss spectroscopy

Electron inelastic mean free paths (IMFP) have been estimated for Ti, TiC, TiN and TiO2 for energies between 250 and 2000 eV. The IMFP values have been derived from the respective energy-loss function (i.e. Im{-1/epsilon}) on the basis of the model developed by Yubero and Tougaard for quantitative analysis using reflection electron energy-loss spectra (REELS). The IMFPs have been analysed in terms of the Bethe equation for inelastic scattering and compared with the values predicted by the TPP-2M equation. We have distinguished between lambda(REELS)(E-0) and lambda(infinity)(E-0), whereby the first takes into account surface effects as they appear in REELS experiments and. (E-0) is the value that is approached when the surface is ignored. The IMFPs determined here are observed to decrease in the order Ti > TiN similar to TiC > TiO2 as the density of valence electrons contributing to inelastic scattering processes increases. Furthermore, we observe a general good agreement with those values predicted by the TPP-2M formulae, except for TiO2 for which differences of up to 30-40% have been observed. Copyright (C) 2002 John Wiley Sons, Ltd.