不同厚度BiFeO_3薄膜的光电性质

Optical and Electrical Properties of BiFeO_3 Films of Different Thicknesses

利用溶胶-凝胶法制备BiFeO_3靶材,通过射频磁控溅射法在玻璃衬底上制备不同厚度的BiFeO_3薄膜,并研究不同厚度对其微观结构、铁电性、漏电流特性及薄膜折射率和消光系数的的影响。结果表明,随着薄膜厚度的增加,铁电性变好,薄膜折射率和消光系数增大,当电压较低时(U1/2<2),Poole-Frenkel机制在漏电特性中起主导作用,当电压较高(1/U<0.25)时,FN隧穿起主导作用;通过拟合图谱计算出不同沉积时间的薄膜厚度及表面层厚度,结果与原子力显微镜测的数值基本一致。

BiFeO3 powder was prepare by Sol-Gel, and BiFO3 films of different thicknesses were deposited on glasses. The effects of different thicknesses on the microstructure, ferroelectricity, leakage current characteristics, refractive index and ex- tinction coefficient of the films were studied. Results showed that with the film becoming thicker, the ferroelectricity improved and the refractive index and extinction increased; when the potential was low （U^1/2 〈2）, Poole-Frenkel was prominent for the leakage current, while FN tunneling had the biggest effect on the leakage current when the potential was high （1/U 〈0.25） ; thickness results of film and surface layer from different deposition times calculated by fitting profile were consistent with the a- tomic force microscope data.