紫光对外延掺锰铁酸铋薄膜物性的影响

Effect of Purple Light on Physical Properties of Epitaxial Mn-doped BiFeO_3 Film

采用溶胶-凝胶的方法在(001)取向的SrRuO3/SrTiO3(SRO/STO)异质结上制备了外延BiFe0.95Mn0.05O3(BFMO)薄膜,并以氧化铟锡(ITO)作为上电极构架了ITO/BFMO/SRO型电容器。研究表明,BFMO薄膜为良好的外延生长,当波长为404 nm的紫光入射到电容器表面,产生光电导,漏电流密度变大;测试电压为5 V时,无光和光照时的漏电流密度分别为2.92 mA/cm2和10.10 mA/cm2。通过对电流密度的拟合发现:欧姆传导为外延ITO/BFMO/SRO电容器的主要漏电机制,并且光照没有改变电容器的导电机制。在紫光照射下,外延ITO/BFMO/SRO电容器的电滞回线发生变化,这是由于光照在薄膜内部产生光生载流子的缘故。由于光辐射的作用,外延ITO/BFMO/SRO电容器的电容增大。

Epitaxial BiFe0. 95Mn0. 05O3（BFMO） film were fabricated on（001）-SrRuO3/ SrTiO3（SRO/ STO） hetero-structure by sol-gel method,and a capacitor with a structure of ITO / BFMO / SRO was constructed. The results show that the photoconduction was produced and the leakage current density increased when the ITO / BFMO / SRO capacitor was exposed to illumination. The leakage current density of ITO / BFMO / SRO capacitor was 2. 92 mA / cm2and 10. 10 mA / cm2measured at 5 V with and without illumination,respectively. Ohmic conduction behavior was the dominated leakage mechanism,and illumination did not change the leakage mechanism. Additionally,Illumination induced variation in the electrical hysteresis loop of ITO / BFMO / SRO capacitor,which can be explained by photo-induced carrier due to illumination. The capacitance of ITO / BFMO / SRO capacitor increases due to the illumination of purple light.