Time dependence of different contributions for the photovoltaic effect in ferroelectric PZT thin films with asymmetric electrodes

In this work the photovoltaic response of ferroelectric Pb(Zr0.20Ti0.80)O-3 (PZT) thin films, with asymmetric Metal/Ferroelectric/Metal structure (Au/PZT/ITO), was investigated and its effect correlated to the ferroelectric and interface properties. We found two effects governing the photovoltaic response in these thin films, a depolarization electric-field (E-dep), dependent on the direction and magnitude of the polarization, and an internal built-in electric field (E-bi) which could be generated by the different electrodes and processing conditions. The time dependence of the photocurrent showed a strong reduction of the photocurrent after poling, probably related to a reaccommodation of charges and back-switching of the polarization, due to the rearrangement of the domain structure in the material.