Effects of grain size and doping on photovoltaic current in (Pb1-xLax)TiO3 ferroelectric ceramics

Abstract

The effects of grain size and doping on the photovoltaic current in (Pb1-xLax)TiO3 ceramics were investigated under uniform illumination. The effects are discussed on the basis of an electro-potential barrier associated with the grain boundary. Photo-excited electrons were trapped at the grain boundary and then built an electro-potential barrier, which impeded the movement of electrons. The maximum photovoltaic current was obtained at the critical grain size; the electro-potential barrier played a minimum role. By increasing the concentration of lanthanum, the critical grain size decreased.