Influence of nonequilibrium electrons on photovoltaic current and domain switching in poled (Pb0.85La0.15)TiO3 ferroelectric ceramics during illumination

Abstract

The variations of photovoltaic current and acoustic emission (AE) event counts with experimental parameters were observed in (Pb0.85La0.15)TiO3 ferroelectric ceramics during illumination in the absence of external electric field. Both photovoltaic current and cumulative AE event counts increased with illumination time. These results could be explained to be associated with the increase in the remanent polarization due to the photoinduced domain switching which resulted from the space charge held established by photoexcited electrons trapped at the grain boundaries. The influence of the experimental parameters on the activity of photoinduced domain switching could be explained in terms of the mechanical strain energy, Delta G(a)(M), which acted as the energy barrier for domain wall motion and the energy associated with space charge held, Delta G(a)(SC), which stimulated domain wall motion.