Seminário do Departamento de Física, CEFITEC e LIBPhys. Nenad Bundaleski (CEFITEC, FCT/UNL): Composition analysis by XPS

Nenad Bundaleski (CEFITEC, FCT/UNL): Composition analysis by XPS

Abstract 

X-ray Photoelectron Spectroscopy (XPS) is a powerful surface sensitive technique providing information on the composition and chemical bonds of surface layers. It is generally considered that the main difficulty in the XPS data analysis is bond interpretation, particularly when photoelectron peaks have several contributions which have to be resolved. On the other hand, the composition analysis, almost exclusively performed by using atomic sensitivity factors, is apparently trivial and reliable due to rather weak matrix effects. In this talk, we explore the applicability of the standard approach to the XPS composition analysis. It will be shown that the application of atomic sensitivity factors is correct only in special cases of single phase surfaces, which are of least interest. In much more common situation, when several phases can be encountered at the surface, XPS can still be used to reveal the phase distribution. Different modelling and experiment strategies, aiming to achieve this goal, will be introduced and illustrated by our laboratory practice.