Direct current bias effects on grain boundary Schottky barriers in CaCu3Ti4O12
Direct current bias effects on grain boundary Schottky barriers in CaCu3Ti4O12
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DOI：
10.1063/1.2172739
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发表时间：
2006-02
影响因子：
4
通讯作者：
Il‐Doo Kim;A. Rothschild;H. Tuller
中科院分区：
文献类型：
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作者：
Il‐Doo Kim;A. Rothschild;H. Tuller
CaCu3Ti4O12具有105量级的高介电常数和高度非线性的I-V特性。在这项工作中进行的阻抗谱测量指出了晶界障碍在控制这种材料的电性能方面所起的关键作用。在直流偏置下，晶界电阻减小，在较高的施加电压下，晶界电阻急剧击穿。势垒高度估计为~ 0.82eV。晶粒电导率从活化能为~ 0.08eV时的负电阻温度系数转变为280℃时的正电阻温度系数，表明在载流子饱和区从杂质电离到散射控制迁移率的转变。
CaCu3Ti4O12 exhibits an unusually high dielectric constant on the order of 105 and highly nonlinear I-V characteristics. Impedance spectroscopy measurements carried out in this work point to the crucial role played by grain boundary barriers in controlling the electrical properties of this material. Under dc bias, the grain boundary resistance decreases, followed by a precipitous breakdown at higher applied voltages. The barrier height is estimated to be ∼0.82eV. The grain conductivity shows a transition from a negative temperature coefficient of resistance with activation energy of ∼0.08eV to a positive temperature coefficient of resistance at 280 °C suggesting a transition from impurity ionization to scattering controlled mobility in the carrier saturation region.