Determining the activation energy of amorphous SrTiO3 film based on thermally stimulated depolarization current

Thermally stimulated depolarization current (TSDC) was investigated on amorphous SrTiO3 film to study the internal polarization mechanism. Three TSDC peaks were observed around 240 K, 270 K and 320 K, respectively. By comparing the experiment results with the theoretical characteristics of three polarization mechanisms, the first peak was assigned to dipole polarization and the second peak was consistent with ionic polarization. The origin of the third peak was ascribed to the trap charge depolarization, since it exhibited a typical linear relation between poling field and square of peak temperatures. In addition, the second peak vanished after the sample had been treated by heating treatment to remove the absorbed water, indicating that the second peak arose from the absorbed water. For the absorbed water, the activation energy of ionic polarization activation energy and ionic conductance are approximately equal, which suggests that ionic polarization charge could turn to be ionic conductance with increasing field.