掺杂对铁酸铋薄膜漏电流及铁电性的影响

铁酸铋是目前最为重要的室温单相多铁性材料,其禁带宽度较小,具有较大的剩余极化强度与较高的铁电居里温度,在铁电随机存储器、光电器件等领域有着极佳的应用前景。但铁酸铋薄膜因Bi3+挥发和Fe3+的部分还原,易产生较大漏电流而制约了其实际应用。对铁酸铋薄膜进行掺杂,是改善其电性能的一种有效手段。围绕如何通过铁酸铋薄膜A位和B位掺杂来减少Bi3+挥发和抑制Fe3+还原,从引入掺杂离子后发生的缺陷反应和微结构变化等方面,对国内外近年来关于铁酸铋薄膜电性能掺杂改性的系列工作进行综述。阐述了A位镧系和碱土金属离子、B位过渡金属离子、A/B位离子共掺对铁酸铋薄膜微结构、漏电流及铁电性等方面的改性研究进展。对改性效果进行了比较,并从缺陷反应、薄膜晶体结构和表面形貌等方面对改性机理进行了详细介绍。此外,还提出了亟待解决的问题。

Effects of Doping on Leakage Current and Ferroelectricity of Bismuth Ferrite Films

Bismuth ferrite is the most important single-phase multiferroic material at room temperature. Because of its small band gap, high remnant polarization and curie temperature, bismuth ferrite is widely used in such fields as ferroelectric random access memory and optoelectronic devices. However, strong leakage current will be produced in bismuth ferrite films due to volatilization of Bi3+ and partial reduction of Fe3+ in preparation process, which restricts its practical application. Doping is an effective method of improving electrical properties of bismuth ferrite films. Centering on the process of reducing volatilization of Bi3+ and inhibiting reduction of Fe3+ by doping at A-B site, recent studies on doping modification of the electrical properties at home abroad were reviewed by analyzing defect reactions and microstructure changes after doping. The modification research progress in effects of lanthanide and alkali metal ions at A-site, transition metal ions at B-site and co-doping at A-B sites on microstructure, leakage current and ferroelectricity was expounded. The modification effects were compared. Moreover, modification mechanism was explained in detail from the aspect of defect reactions, crystal structure and surface morphology. Finally, some urgent questions to be solved were put forward.