The influence of oxygen deficiency on the thermoelectric properties of strontium titanates

We report oxygen reduction in bulk strontium titanate substrates when a thin film was deposited in an oxygen-deficient environment. The oxygen diffusion occurred at moderate temperatures and oxygen pressures, which were not enough to produce detectable oxygen vacancies without the film deposition. In order to identify the reduction, we used a series of different annealing conditions and various substrates and performed comparative studies regarding thermoelectric properties before and after removing the films. Our experimental results suggest that the measurements of material properties of thin films on SrTiO3 single crystal substrates need to be performed carefully due to its strong susceptibility to oxygen deficient condition