Photovoltaic Effect Based on Polarization Charge in Polycrystalline Pb(ZrTi)O3 Film

A steady-state short-circuit photocurrent across polycrystalline Pb(ZrTi)O-3(PZT) film is found to be directed opposite to ferroelectric polarization, defined by the magnitude of polarization, but it is not the depolarization current of the ferroelectric. To explain this, the authors assume that Pt/PZT/Ir capacitor consists of PZT grains and semiconductor PbO phase segregated on PZT grain boundaries and forming conducting channels. In such medium, uncompensated polarization charge can arise at the PZT/PbO interface and generate the electric field acting on carriers in PbO channels, thus producing the photocurrent across the film. The relation between the polarization charge and electric field is considered.