Oxygen incorporation from CO2 and H2O in Fe-doped SrTiO3 single crystals

Strontium titanate is a promising candidate for the development of a new generation of resistive high temperature oxygen sensors. The analysis of automobile exhaust is regarded as a possible main application. An interpretation of the sensors signal in such an environment will only be possible with an understanding of the cross-sensitivity of the strontium titanate for other present gases like water or carbon dioxide. Our results for the interaction of donor-doped strontium titanate single crystals with these species are presented in this poster. Metastable induced electron spectroscopy and ultraviolet photoelectron spectroscopy are used to study adsorption and dissociation processes under ultra high vacuum conditions. Oxygen tracer diffusion experiments performed under realistic conditions using secondary ion mass spectroscopy as well as investigations with X-ray photoelectron spectroscopy and temperature programmed Desorption give evidence to the oxygen incorporation into the strontium titanate. Furthermore, diffusion processes can be investigated. We correlate the results to develop a model for the occurring interaction processes