Surface excitation of selected conducting polymers studied by elastic peak electron spectroscopy (EPES) and reflection electron energy loss spectroscopy (REELS)

Abstract

AbstractElectrons impinging into a solid surface produce excitations in the surface layer. The elastic reflection coefficient of a solid (i.e. elastic peak) is reduced by surface losses. Selected conducting polymers were studied with elastic peak electron spectroscopy (EPES) and reflection electron energy loss spectroscopy (REELS). The electron inelastic mean free path (IMFP) was determined using EPES with Ag and Si references and corrected for surface excitations, characterized by the surface excitation parameter Pse(E). A new procedure was developed for experimental determination of the parameter Pse(E), a further development of Tanuma's work. It is based on comparison of experimental and calculated integrated elastic peak ratios of sample and reference. Another procedure was based on the REELS method. Pse(E) of selected polymers were determined for E = 0.2–2.0 keV using a HSA analyser. Experiments were evaluated by Monte Carlo simulation using NIST elastic scattering databases. The IMFP values for polymers were calculated by Gries, Cumpson and TPP‐2M formulae. Material parameter data, ach, using Chen's approach for selected polymers, and IMFPs of polyethylene corrected for surface excitation are presented. Copyright © 2004 John Wiley & Sons, Ltd.