Elucidation of mechanism on photo-induced electrical properties developing in narrow-bandgap ferroelectric material thin films

采用化学溶液沉积法制备了窄禁带铁电薄膜，并研究了薄膜在可见光照射下的光致电学性质。通过光生电流的行为，证实了制备后薄膜中自偏置电场的存在。此外，带隙和铁电性质对光生电学性质有很大的影响，极化处理可以改变极化方向，当施加的电场大于矫顽场时，极化处理可以改变光生电流和光电压。为了进一步提高复合材料的性能，制备贵金属纳米颗粒复合材料是有效的。

Fabrication of narrow bandgap ferroelectric thin films was carried out by the chemical solution deposition process that chemical composition control was facile, and the elucidation of photo-induced electrical properties under the visible light irradiation was performed. The existence of the self-bias electric field in the film after the preparation was clarified by the behavior of the photo-induced electric current. In addition, photo-induced electrical properties were greatly influenced by bandgap and ferroelectric properties, the polarization direction could turn over the photo-induced current and photovoltage by poling treatment with applying an electric field more than a coercive field. For the further properties improvement, it was effective to prepare the composites with noble metal nanoparticles.