Stability and magnitude of photovoltage in ferroelectric (Pb 0.97La0.03)(Zr0.52Ti0.48)O 3 thin films in multi-cycle uv light illumination

Abstract

The stability and magnitude of photovoltage response in (Pb 0.97La0.03)(Zr0.52Ti0.4g)O 3 (PLZT) ferroelectric thin films were investigated in the present work. Photovoltage degrading in multi-cycle ultraviolet (UV) light illumination was observed in Au/PLZT/Pt sandwich capacitor configuration and in-plane polarized configuration with a pair of top Au interdigital electrodes. For the in-plane polarized configuration, which had a greatly enhanced electrode gap, the reduction ratio of photovoltage during multi-cycle UV illumination was significantly smaller hence the stability of photovoltage was greatly improved over the sandwich capacitor configuration. Trapping of photo-induced charges and polarization screening at the ferroelectric-electrode interfaces were found to be the major cause for the degrading of photovoltage in ferroelectric films. Furthermore, for the Au/PLZT/Pt capacitor, the magnitude and even the polarity of the photovoltage were remarkably affected by the asymmetric interfacial Schottky barriers due to the small photovoltage magnitude determined by the small film thickness.