Oxygen diffusion process in a Ba0.96La0.04SnO3 thin film on SrTiO3(001) substrate as investigated by time-dependent Hall effect measurements

We investigate the oxygen diffusion phenomena in a Ba0.96La0.04SnO3 (BLSO) thin film on SrTiO3(001) substrate by measurements of time-dependent Hall effect at high temperatures around 500 degrees C under different gas atmosphere. Under the Ar (O-2) atmosphere, carrier density (n) and electrical conductivity (sigma) are increased (decreased) while electron mobility (mu) is slightly reduced (enhanced). This observation supports that although both n and mu are affected by the oxygen diffusion process, the change of n is a major factor of determining s in the BLSO film. Detailed analyses of the time-dependent n exhibit fast and slow dynamics that possibly correspond to the oxygen exchange reaction at the surface and oxygen diffusion into the BLSO grains, respectively. Fitting the time dependence of n reveals that the chemical diffusion coefficient of oxygen in the BLSO grains becomes similar to 10(-16)cm(2) s(-1). This coefficient marks the lowest value among perovskite oxides around 500 degrees C, directly proving excellent thermal stability of oxygen in BLSO. The present results support that the donor-doped BaSnO3 system could be useful for realizing transparent semiconductor devices at high temperatures. (C) 2015 WILEY - VCH Verlag GmbH & Co. KGaA, Weinheim