Far infrared reflection spectra of InAs x Sb 1- x (x = 0-0.4) thin films
Far infrared reflection spectra of InAs x Sb 1- x (x = 0-0.4) thin films
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DOI：
10.1063/1.4809045
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发表时间：
2013-06
影响因子：
3.2
通讯作者：
Li Huang;Zhifeng Li;Pingping Chen;Yihui Zhang;W. Lu
中科院分区：
文献类型：
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作者：
Li Huang;Zhifeng Li;Pingping Chen;Yihui Zhang;W. Lu
本文研究了一系列InAs_xSb_1_−_x三元薄膜(x=0~0.4)在室温下50~4,000 cm−_1波段的远红外反射特性。用多振子模型对得到的光谱进行了拟合。在x>；0样品中发现了两种晶格振动模式，即类InSb和类InAs，外加一种等离子体激元模式。这些三元合金薄膜中的晶格振动呈现典型的双模行为。在所研究的分数范围内，InSb横向光学(TO)声子频率随x的增大而减小，而InAs声子频率随x的增大而增大。用随机元等位移模型描述了声子频率的变化。用拟合出的等离子体激元参数来提取载流子浓度和迁移率。载流子浓度随As含量的增加而单调增加，并归因于禁带宽度变窄效应。迁移率随着x的增加而减小，表明散射增加。
A series of InAs x Sb1− x ternary thin films (x = 0-0.4) has been studied in a far-infrared reflection experiment over the range of 50-4000 cm−1 at room temperature. The obtained spectra are fitted using a multi-oscillator model. Two types of lattice vibration modes, InSb-like and InAs-like, plus one plasmon mode have been identified in x > 0 samples. The lattice vibration in these ternary alloy films shows a typical two-mode behavior. Within the studied fraction range, the InSb transverse-optical (TO) phonon frequency decreases with x, while the InAs TO frequency increases. A random-element-isodisplacement model has been employed to describe the phonon frequency changes. The fitted plasmon parameters have been used to extract the carrier concentrations and mobility. The carrier concentration increases monotonously with the increase of As fraction and is attributed to the bandgap narrowing effect. The mobility decreases with x, indicating an increased scattering.