Nonsteady-State Photovoltaic Current and Photoinduced Domain Switching in Poled (Pb0.85La0.15)TiO3 and BaTiO3 Ferroelectric Ceramics

Abstract

In (Pb0.85La0.15)TiO3 and BaTiO3 ferroelectric ceramics under illumination in the absence of an external electric field, we observed that photovoltaic current increased with illumination time. On the basis of the absence of pyroelectric current just after light-off and the acoustic emission (AE) signals detected during illumination, the nonsteady-state photovoltaic current behavior was attributed to the increase in remanent polarization, related to the increase in spontaneous polarization, and photoinduced domain switching, both of which resulted from the space charge field established by photoexcited electrons trapped at the grain boundaries. The influence of the poling field on the photoinduced domain switching activity could be explained in terms of the mechanical strain energy, which acted as the energy barrier for domain wall motion, and the energy associated with the space charge field which stimulated domain wall motion.