Effective depths for surface excitation derived by reflection electron energy-loss spectroscopy analysis

A method of estimation is proposed for determining the effective depth of surface excitation. For this, the effective differential inverse inelastic mean free path (DIIMFP) is presumed to be represented as a linear combination of theoretical DIIMFPs for surface and bulk excitation, which are derived by the use of optical dielectric constants. The effective DIIMFP in the approach is derived by a reflected electron energy-loss spectroscopy analysis based on the extended Landau approach. The present analysis for 1 kV electrons has led to a simple estimation of the effective depth for surface excitations (similar to14.5 Angstrom for Al and similar to21 Angstrom for Ag), agreeing well with an estimation given by v/(omega) over bar (s), where v and (omega) over bar (s) are the velocity of the primary electrons and the average surface plasmon frequency, respectively. Copyright (C) 2004 John Wiley Sons, Ltd.