外延掺锰铁酸铋薄膜电容器的光电导和光伏效应  

Photoconductivity and Photovoltaic Effect of Epitaxial Mn-doped BiFeO3 Thin Film Capacitor

作　　者：彭增伟[1] 刘保亭[2] PENG Zengwei;LIU Baoting(College of Science and Technology,North China Electric Power University,Baoding 071051,China;College of Physics Science and Technology,Hebei University,Baoding 071002,China)

机构地区：[1]华北电力大学科技学院,保定071051 [2]河北大学物理科学与技术学院,保定071002

出　　处：《材料导报》2020年第6期10-14,共5页Materials Reports

基　　金：中央高校基本科研业务费专项资金(2016MS157);国家自然科学基金(11374086);河北省自然科学基金(A2018201168)~~

摘　　要：采用射频磁控溅射的方法在SrRuO 3/SrTiO 3(SRO/STO)衬底上制备了外延Mn掺杂的BiFeO 3(BFMO)薄膜,并以Pt/SRO为复合上电极构建了对称的SRO/BFMO/SRO薄膜电容器。X射线衍射揭示了BFMO薄膜具有良好的外延结构。极化-电场滞后回线、净极化强度的测试结果说明外延SRO/BFMO/SRO电容器具有较大的剩余极化强度。波长为404 nm、强度为5 mW/cm 2的紫光入射到SRO/BFMO/SRO电容器表面,电流密度相应增长。当测试电压为+8 V,无光和光照时的电流密度分别为0.14 A/cm 2和0.34 A/cm 2;当测试电压为-8 V,无光和光照时的电流密度分别为0.13 A/cm 2和0.33 A/cm 2。通过对电流密度的拟合发现:无光和光照时均为欧姆传导机制,光照并没有改变SRO/BFMO/SRO电容器的传导机制。SRO/BFMO/SRO电容器的光伏效应主要由薄膜内部极化决定。与纯BFO薄膜电容器相比,Mn掺杂增大了光伏输出的短路电流密度。Epitaxial Mn-doped BiFeO 3(BFMO)thin film was directly deposited on SrRuO 3(SRO)buffered(001)-orientation SrTiO 3(STO)substrate by radio frequency magnetron sputtering.Using integrated Pt/SRO to be top electrode to form the symmetric SRO/BFMO/SRO capacitor.X-ray diffraction discovers that BFMO film is of good epitaxial structure.Polarization-electric field hysteresis loops and pulsed polarization show that epitaxial SRO/BFMO/SRO capacitor possesses excellently ferroelectric polarization.The increased leakage current density is acquired when the SRO/BFMO/SRO capacitor is illuminated by the purple light of 5 mW/cm 2 with a wavelength of 404 nm.The leakage current density is 0.14 A/cm 2 and 0.34 A/cm 2 at 8 V without and with illumination,and 0.13 A/cm 2 and 0.33 A/cm 2 at-8 V without and with illumination,respectively.The ohmic conduction is the dominated leakage mechanism which is not changed by illumination.Photovoltaic effect of the SRO/BFMO/SRO capacitor is mainly controlled by the ferroelectric polarization.Mn doping increases the short circuit current density in photovoltaic effect of the SRO/BFMO/SRO capacitor,compared with that of pure BiFeO 3 film capacitor.

关 键 词：掺杂 锰 铁酸铋薄膜 光电导 光伏效应 

分 类 号：O484.1[理学—固体物理] O482.7[理学—物理]