King's College London, Department of Physics, Strand, London, UK.
J Phys Condens Matter. 2010 Dec 22;22(50):505801. doi: 10.1088/0953-8984/22/50/505801. Epub 2010 Nov 26.
At room temperature, the ν(3) (1136 cm(-1)) absorption band of oxygen in silicon and Si(1 - x)Ge(x) alloys consists of dozens of components, masking the properties of the individual transitions. Here, experimental data are presented for the evolution of the ν(3) band in the temperature range 0 < T < 300 K and the composition range 0 ≤ x ≤ 0.066. The vibrational potential for Si:O is developed to provide accurate fits to the absorption data. The potential predicts properties consistent with published studies, including hydrostatic stress experiments. Extending the model to Si(1 - x)Ge(x) allows the properties of the alloy-induced O(i)-I, O(i)-II and O(i)-III components to be investigated accurately to higher values of x than hitherto. The properties of O(i)-I are understood as perturbations by Ge atoms of Si:O, and O(i)-III is rationalized in terms of off-axis movement of the O atom resulting from the nearby Ge atom. Challenges to theory are: the behaviour of O(i)-II, understanding the strain fields generated by Ge atoms in Si, and the reduced coupling of the ν(2) and ν(3) modes with increasing amplitude in the ν(2) mode.
在室温下，硅和 Si(1-x)Ge(x) 合金中氧的 ν(3)（1136cm-1）吸收带由几十个分量组成，掩盖了各个跃迁的性质。这里，给出了 ν(3) 带在 0 < T < 300K 和 0 ≤ x ≤ 0.066 的组成范围内的温度范围内的演化的实验数据。为 Si:O 开发了振动势能，以提供对吸收数据的精确拟合。该势预测的性质与已发表的研究一致，包括静压实验。将模型扩展到 Si(1-x)Ge(x) 中，可以准确地研究合金诱导的 O(i)-I、O(i)-II 和 O(i)-III 分量的性质，直到 x 的值高于以往。O(i)-I 的性质被理解为 Ge 原子对 Si:O 的微扰，O(i)-III 则可以用 O 原子由于附近的 Ge 原子而偏离轴的运动来合理化。对理论的挑战是：O(i)-II 的行为，理解 Ge 原子在 Si 中产生的应变场，以及随着 ν(2)模式振幅的增加，ν(2)和 ν(3)模式的耦合减少。
