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The stability and magnitude of photovoltage response in (Pb0.97La0.03)(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. [ABSTRACT FROM AUTHOR]

Photovoltaic effect in ferroelectric materials exhibits potential for applications of sensors and remote controls in micro-electro-mechanical systems, and a systematic evaluation on the photovoltaic behavior in ferroelectric materials becomes important. However, as a critical parameter that determines the photovoltaic output in ferroelectric thin films, the film thickness effect on photocurrent output has not been investigated for thin film samples. In this work, a theoretical model has been developed to describe the thickness-dependent photocurrent in (Pb0.97La0.03)(Zr0.52Ti0.48)O3(PLZT) thin films with a sandwich electrode structure. This model indicates that photocurrent increases exponentially with the decrease in film thickness. Therefore, a significantly enhanced photocurrent can be expected in thinner PLZT films. The predicted thickness dependence of the short circuit photocurrent was also supported by our experimental results. [ABSTRACT FROM AUTHOR]