Free-energy model for bonding in amorphous covalent alloys.
Free-energy model for bonding in amorphous covalent alloys.
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DOI：
10.1103/physrevb.43.4507
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发表时间：
1991-02
期刊：
影响因子：
--
通讯作者：
Yin;Smith
中科院分区：
文献类型：
--
作者：
Yin;Smith
开发了一种用于非晶共价合金键合的自由能模型 (FEM)，并将其应用于三元 a-Si x N y H z 合金系统。混合吉布斯自由能 G M= H M-TS M 是通过使用常规溶液热力学的准化学方法获得的。混合焓 H M 以最近邻键能表示，而混合熵 S M 由 Si 中心四面体中可能的键构型数量给出。这些合金中的化学排序 (CO) 与优先选择 Si-N 和 Si-H 键相对应，而牺牲了 Si-Si 和 NH 键。 FEM 的预测结果与实验确定的 a-Si x N y H z 合金薄膜中的键浓度非常一致，其中，一般来说，CO (T= 0 K) 和随机键限制均无效。
A free-energy model (FEM) for bonding in amorphous covalent alloys is developed and applied to the ternary a-Si x N y H z alloy system. The Gibbs free energy of mixing G M= H M-TS M is obtained with use of the quasichemical approach to the thermodynamics of regular solutions. The enthalpy of mixing, H M, is expressed in terms of the nearest-neighbor bond energies, while the entropy of mixing, S M, is given by the number of possible bonding configurations in Si-centered tetrahedra. Chemical ordering (CO) in these alloys is shown to correspond to the preference for Si-N and Si-H bonds at the expense of Si-Si and NH bonds. The predictions of the FEM are shown to be in good agreement with experimentally determined bond concentrations in a-Si x N y H z alloy films where, in general, neither the CO (T= 0 K) nor random-bonding limits are valid.