Anomalously large measured thermoelectric power factor in   Sr$_{1-x}$La$_x$TiO$_3$ thin films due to SrTiO$_3$ substrate reduction
  We report the observation that thermoelectric thin-films of La-doped SrTiO3 grown on SrTiO3 substrates yield anomalously high values of thermopower to give extraordinary values of power factor at 300K. Thin-films of Sr0.98La0.02TiO3, grown via pulsed laser deposition at low temperature and low pressure (450C, 10-7Torr), do not yield similarly high values when grown on other substrates. The thin-film growth induces oxygen reduction in the SrTiO3 crystals, doping the substrate n-type. It is found that the backside resistance of the SrTiO3 substrates is as low (~12ohm/square) as it is on the film-side after film growth. 
Matthew L. Scullin (1 and 2), Choongho Yu (1 and 3), Mark Huijben (2   and 5), Subroto Mukerjee (5), Jan Seidel (5), Qian Zh...