Adsorbed layer and thin film growth modes monitored by Auger electron spectroscopy

Quantitative surface chemistry depends crucially on an accurate analysis of adsorbed quantities in the range from submonolayer coverages to several monolayers. Auger electron spectroscopy is a routinely used technique. For metallic adsorbates, used for example to modify the substrate reactivity, calibration is often made from observations of changes in Auger signals with time during film growth (AS-t plots). A critical review of this technique is presented. Topics discussed include: distinguishing various growth modes; the use of associated techniques; monolayer “étalons”; multilayers; alloying and compound formation; coadsorption and the formation of bi-layers. Errors and ambiguities of interpretation are not uncommon; various pitfalls are discussed. A bibliographic compilation is presented as a guide to some 440 investigations (1968–1988) of 220 adsorbate/substrate systems.