Quantitative analysis of REELS spectra of ZrO 2 : Determination of the dielectric loss function and inelastic mean free paths

The dielectric loss function of ZrO 2 over 0–80 eV has been determined from a quantitative analysis of reflection electron energy loss spectra (REELS) at different primary energies. From this, the inelastic electron mean free path for 200–2000 eV electrons in ZrO 2 has been calculated. The inelastic mean free path (IMPF) is found to depend on the depth from which the electron is backscattered. For great depths, the IMFP approaches a constant value which is the same as that which would be obtained within a model that ignores the effects of the surface. The derived IMFP values have been compared to different formulae presented in the literature and the TPP2 formula due to Tanuma et al. is found to give the best agreement with the present results.