Parallel syntheses and thermoelectric properties of Ce-doped SrTiO3 thin films

Abstract Thermoelectric properties of single crystalline Ce x Sr 1− x TiO 3 films (0 ≤  x  ≤ 0.5) have been studied by using combinatorial pulsed-laser deposition. Temperature gradient method was used for identifying an optimum growth temperature for SrTiO 3 homoepitaxial growth, at which both oxygen stoichiometry and persisting layer-by-layer growth mode could be accomplished. Electrical conductivity ( σ ) and Seebeck coefficient ( S ) were measured at room temperature for the composition-spread films grown at the optimized temperature and found to be considerably higher than those reported for bulk poly-crystalline compounds. Hall measurement revealed that carrier density linearly increased with increasing x , suggesting that a trivalent Ce ions substituted divalent Sr ions to supply electrons. A maximum power factor ( S 2 σ ) was obtained for the x  = 0.2 film, being 7 and 14 μW/K 2  cm at 300 and 900 K, respectively.