DERIVATION OF NEW ENERGY-LOSS FUNCTIONS AS APPLIED TO ANALYSIS OF SI 2P XPS SPECTRA

New energy-loss functions for Si 2p photoelectrons have been derived f rom reflection electron energy-loss spectroscopy (REELS) spectra using a Landau formulation modified to account for elastic scattering. Thes e energy-loss functions revealed significant contributions from occupi ed surface states, as well as from interband transitions in addition t o surface and bulk plasmon excitations. They contribute to a broadenin g of the signal characteristic of the bulk and surface plasmon excitat ions. Monte Carlo simulation based on the use of the new energy-loss f unctions appears to describe very well the energy-loss structure in RE ELS spectra measured under different experimental conditions. These ne w energy-loss functions have also been effectively applied to backgrou nd subtraction from X-ray photoelectron spectroscopy (XPS) spectra to derive more precise source functions of Si 2p photoelectrons. These so urce functions, when applied to two XPS spectra measured under quite d ifferent experimental conditions, showed good agreement.