Interaction of Pd-overlayers with SnO2 : comparative XPS, SIMS, and SNMS studies

We report about interaction processes between palladium (Pd) and tin dioxide (SnO2) studied with various surface spectroscopic techniques. Total sputter yields necessary for absolute depth calibration in SIMS are determined for SnO2. Clustering of palladium occurs at low temperatures. Small changes in the XPS relative core level intensities of Pd and Sn allow to determine cluster sizes. Oxidation of Pd in the presence of oxygen at T≥470 K is a prerequisite for diffusion of Pd2+ ions into SnO2 layers. The latter process is confirmed and described quantitatively by evaluating the SIMS and SNMS measurements.