Determination of Submonolayer Coverages Using Auger Escape Depths

A simple method for determining submonolayer adsorbate coverages by means of Auger electron spectroscopy is presented. The procedure is based on the ratio of low to high kinetic energy Auger signals from the substrate alone, therefore it does not require a direct measurement of adsorbate peaks. It may be of special interest in cases where the adsorbate signal is difficult or impossible to measure, as well as when adsorbate and substrate peaks overlap or when peaks are absent (H or He) or of low intensity. The method is tested by quantification of sulphur layer on the Ni(001) and on the polycrystalline iron surface.