Novel electrical conductivity properties in Ca-doped BiFeO3 nanoparticles
Novel electrical conductivity properties in Ca-doped BiFeO3 nanoparticles
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DOI：
10.1007/s11051-015-3018-1
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发表时间：
2015-05
影响因子：
2.5
通讯作者：
X. Wang;S. Wang;W. Liu;X. Xi;H. Zhang;F. Guo;X. L. Xu;M. Li;Liyuan Liu;C. Zhang
中科院分区：
文献类型：
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作者：
X. Wang;S. Wang;W. Liu;X. Xi;H. Zhang;F. Guo;X. L. Xu;M. Li;Liyuan Liu;C. Zhang
研究了 140 至 25 nm 的 Bi1−xCaxFeO3(CBFO,x= 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) 纳米颗粒 (NP) 中的电荷缺陷结构及其与带隙和漏电流行为的关系。结果表明，由于氧空位的出现和积累，Ca 掺杂有效地将带隙从 ~2.16 eV 缩小到 ~2.02 eV。随后，这些 CBFO NP 获得了增强的电导率，这导致在室温下具有更高电导率的 Ca 掺杂 BFO NP 中出现明显的阈值转换行为。通过X射线光电子能谱分析，在颗粒尺寸减小和氧空位密度增加的基础上，根据纳米颗粒尺寸效应和移动带电缺陷的相互作用，讨论了Ca掺杂对导电影响的可能机制。
The charge defective structure in Bi1−xCaxFeO3(CBFO,x= 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) nanoparticles (NPs) ranging from 140 to 25 nm as well as their relations to band gap and leakage current behavior are investigated. It is demonstrated that Ca doping effectively narrows the band gap from ~2.16 to ~2.02 eV, due to the appearance and accumulation of oxygen vacancy. Subsequently, enhanced electrical conductivity was obtained in these CBFO NPs, which leads to the appearance of a distinct threshold switching behavior in Ca-doped BFO NPs with higher conductivity at room temperature. Possible mechanisms for Ca doping effects on the electric conduction were discussed upon the interplay of NPs’ size effect and mobile charged defects on the basis of reduced particle size and the increased density of oxygen vacancy analyzed through X-ray photoelectron spectrum.