Absolute determination of the stoichiometry of ultra-thin oxide films as afunction of thickness: antimony oxide on gold

Oxide layers only a few atomic layers thick are important in electronic dev ices and heterogeneous catalysis. This has led to the need to understand be tter the evolution of the oxide stoichiometry with thickness in such situat ions. This paper shows that a high-stability quartz-crystal microbalance ca n provide absolute measurements of changes in the stoichiometry of oxides a s they evolve one molecular layer at a time. In the case of ultra-thin anti mony oxides grown on a gold substrate, the compound SbAuO was observed for Sb deposits of less than 1.6 atomic lavers. This oxide acts as a transition layer between the gold and subsequent oxide layers which are Sb2O3. (C) 20 01 Elsevier Science B.V. All rights reserved.