Photovoltaic and Ferroelectric Properties of Pb0.95La0.05Zr0.54Ti0.46O3 Thin Films under Dark and Illuminated Conditions

Abstract

Thin films of Pb0.95La0.05Zr0.54Ti0.46O3 were prepared using chemical solution method. The photovoltaic response of the films under dark and illuminated conditions was investigated using capacitor type devices with Pt as top and bottom electrodes. The results show that the open circuit voltage and the short circuit current of a capacitor type cell can be manipulated by controlling the post deposition annealing temperature of the films. Films annealed at 750°C were seen to exhibit the highest short circuit current of 15.83 nA. The influence of illumination on properties such as capacitance, ferroelectric polarization and leakage current was studied. The capacitance of the film was seen to decrease when illuminated with light (60mW/cm2), suggesting that illumination leads to generation of charge carriers. The films became leaky under illumination, resulting in an increase in leakage current by an order of magnitude compared to the dark conditions. The saturation polarization (Ps) was suppressed, whereas the remnant polarization (Pr) was not affected under illumination. Further, a shift in the hysteresis loop, along the voltage axis, was observed under illuminated conditions. This shift is attributed to the change of a space-charge field with illumination.