Oxidation of nanostructured Ti films produced by low energy cluster beam deposition: An X-ray Photoelectron Spectroscopy characterization

We used in-situ X-ray Photoelectron Spectroscopy (XPS) to study the oxidation process of a clusterassembled metallic titanium film exposed to molecular oxygen at room temperature. The nanostructured film has been grown on a Si(111) substrate, in ultra high vacuum conditions, by coupling a supersonic cluster beam deposition system with an XPS experimental chamber. Our results show that upon in-situ oxygen exposure Ti3+ is the first oxidation state observed, followed by Ti4+, whereas Ti2+ is practically absent during the whole process. Our results compare well with the existing literature on Ti films produced using other techniques.