While SrTiO3 exhibits promising electronic transport properties, its high thermal conductivity (κ) is detrimental for its use as a thermoelectric material. Here, we investigate the influence of oxygen non-stoichiometry on κ in bulk SrTiO3 ceramics. A significant reduction in κ was achieved in oxygen deficient SrTiO3−δ, owing to the presence of oxygen vacancies that act as phonon scattering centers. Upon oxidation of SrTiO3−δ, the κ of pristine SrTiO3 was recovered, suggesting that oxygen vacancies were indeed responsible for the reduction in κ. Raman spectroscopy was used as an independent tool to confirm the reduction of oxygen vacancies in SrTiO3−δ upon oxidation.
KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The research was supported by KAUST-Clemson Faculty Initiated collaboration grant. The authors would like to thank W.G. Nilsen and J.G. Skinner for the reprint their Raman spectra to directly compare with our Raman spectra. The authors would like to acknowledge useful discussions with Dr. Colin McMillen (Clemson University) on the XRD analysis of these samples and Mr. Herbert Behlow on stoichiometric analysis.