Electrical and optical properties of thin Fe1−xCoxSi2 films
Electrical and optical properties of thin Fe1−xCoxSi2 films
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Fe1−xCoxSi2 薄膜的电学和光学特性
DOI：
10.1016/0169-4332(95)00094-1
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发表时间：
1995
影响因子：
6.7
通讯作者：
D. Panknin
中科院分区：
文献类型：
--
作者：
S. Teichert;R. Kilper;T. Franke;J. Erben;P. Häussler;W. Henrion;H. Lange;D. Panknin
通过直流溅射Co掺杂硅化物靶材并沉积在加热的石英衬底上，制备了Fe1−xCoxSi2薄膜。在300~25K温度范围内，用范德波法进行了电阻率和霍尔系数的电学测量。室温下的霍尔迁移率低于1cm2V−1s−1，表明样品中的杂质对电输运性质有很大的影响。用假设磁序的模型解释了低温下霍尔电阻率与磁场的非线性关系。随着薄膜中Co含量的增加，霍尔系数的符号由正变负。这可以用样品中给体浓度的增加来解释。随着硅含量的增加，Co掺杂样品的导电类型由n型向p型转变，向低温方向移动。光学测定的直接能隙能随Co浓度的增加而线性地向较低的能级移动。这一结果可以用包含成分无序的虚拟晶场近似来解释。
Thin Fe1−xCoxSi2films were prepared by DC sputtering of Co-doped silicide targets and deposition onto heated quartz substrates. Electrical measurements for the determination of resistivity and Hall coefficient were performed in the temperature range from 300 to 25 K by a van der Pauw method. The Hall mobility at room temperature is below 1 cm2V−1s−1, indicating a strong influence of the impurities in the samples on the electrical transport properties. The nonlinear dependence of the Hall resistivity versus the magnetic field at low temperatures is explained by a model assuming magnetic ordering. The sign of the Hall coefficient changes from positive to negative with increasing Co concentration in the films. This could be explained by an increasing of the donor concentration in the samples. The observed change of conduction type from n to p in Co-doped samples shifts to lower temperatures by increasing the silicon content. The optical determined direct gap energy shifts linearly with increasing of the Co concentration to lower energies. This result is explained in terms of a virtual crystal field approximation including compositional disorder.