Seebeck coefficients and conductivity of La-doped SrTiO3 thin films grown by molecular beam epitaxy were measured as a function of carrier concentration. At low carrier concentrations, thin films show very high Seebeck coefficients (up to 980 μV K-1). The maximum thermoelectric power factor was 39 μW cm-1 K-2 at a carrier concentration of 7× 1020 cm-3. La-delta-doped superlattices were also characterized and exhibited Seebeck coefficients of ∼500 μV K -1. The results are discussed in the context of reports of enhanced Seebeck coefficients in delta-doped SrTiO3 superlattices.
Bibliographical noteFunding Information:
The work was supported by the U.S. Department of Energy, Basic Energy Sciences (Grant No. DE-FG02-02ER45994). B.J. would like to thank Ashok Ramu for his help with the Seebeck measurements and for many useful discussions. The authors also thank John Bowers for allowing the use of his set-up for Seebeck measurements, which is supported as part of the Center for Energy Efficient Materials, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Basic Energy Sciences.