High-temperature thermoelectric response of double-doped SrTiO3 epitaxial films

SrTiO3 is a promising n -type oxide semiconductor for thermoelectric energy conversion. Epitaxial thin films of SrTiO3 doped with both La and oxygen vacancies have been synthesized by pulsed laser deposition. The thermoelectric and galvanomagnetic properties of these films have been characterized at temperatures ranging from 300 to 900 K and are typical of a doped semiconductor. Thermopower values of double-doped films are comparable to previous studies of La-doped single crystals at similar carrier concentrations. The highest thermoelectric figure of merit (ZT) was measured to be 0.28 at 873 K at a carrier concentration of 2.5× 1021 cm-3. © 2010 The American Physical Society.