Composition dependence of dielectric function in ferroelectric BaCoxTi1−xO3 films grown on quartz substrates by transmittance spectra
Composition dependence of dielectric function in ferroelectric BaCoxTi1−xO3 films grown on quartz substrates by transmittance spectra
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DOI：
10.1063/1.2870094
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发表时间：
2008-02
影响因子：
4
通讯作者：
Zhigao Hu;Y. W. Li;M. Zhu;Zhifeng Zhu;J. Chu
中科院分区：
文献类型：
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作者：
Zhigao Hu;Y. W. Li;M. Zhu;Zhifeng Zhu;J. Chu
通过透射光谱研究了BaCoxTi 1 − xO 3（BCT）（x从1.0%到10%）薄膜的近红外-紫外光学特性。用阿达奇模型对实验数据进行拟合，得到了光子能量在1.24-6.2eV范围内的色散函数。研究发现，BCT材料的振子能和色散能随着Co成分的增加而线性增加，最大光学跃迁发生在4.3-5.0eV的能量范围附近。由于晶界和无序诱导的带尾进入禁带，可见光区的吸收系数随组分的增加而线性增加。
Near-infrared-ultraviolet optical properties of BaCoxTi1−xO3 (BCT) (x from 1.0% to 10%) films have been investigated by the transmittance spectra. The dispersion functions in the photon energy range of 1.24–6.2eV have been extracted by fitting the experimental data with Adachi’s model. It was found that the oscillator and dispersion energies linearly increase with the Co composition and the maximum optical transition occurs near the energy range of 4.3–5.0eV for the BCT materials. The absorption coefficient at the visible region linearly increases with the composition due to grain boundaries and disorder induced band tail into the forbidden gap.