Applications of Huang–Rhys theory in semiconductor optical spectroscopy
Applications of Huang–Rhys theory in semiconductor optical spectroscopy
复制标题
Huang-Rhys理论在半导体光谱中的应用
DOI：
10.1088/1674-4926/40/9/091102
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发表时间：
2019
影响因子：
5.1
通讯作者：
Yong Zhang
中科院分区：
文献类型：
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作者：
Yong Zhang
简要回顾了黄-里斯理论和阿尔布雷希托斯理论，讨论了它们之间的联系和应用。前者是光学跃迁的一阶微扰理论，适用于涉及局部缺陷或杂质中心的吸收和发射等应用，强调晶格弛豫或由于电子-声子耦合引起的振动态混合。耦合强度由Huang-Rhys因子描述。后一种理论是用于拉曼散射的光学跃迁的二阶微扰理论，并且原则上可以包括电子态和振动态中的电子-声子耦合。这两个理论可以潜在地通过晶格弛豫的共同效应-与不同电子态相关的非正交振动态-连接起来。由于这种感知的联系，后者的理论通常被用来解释共振拉曼散射的LO声子在体半导体和进一步用于描述的尺寸依赖性的电子-声子耦合或黄-里斯因子在半导体纳米结构。具体地说，在文献中，由于自由激子可能具有强晶格弛豫的误解，Albrechtos理论中的A项经常被调用来描述块体和纳米结构半导体中的多LO声子共振拉曼峰。在没有晶格弛豫的情况下，A项将引起瑞利散射或弹性散射。晶格弛豫仅对高度局域化的缺陷或杂质态有意义，并且对于体半导体中的单粒子态或自由激子态或对于不是极小的半导体纳米结构中的受限态，晶格弛豫实际上应该为零。
A brief review of Huang–Rhys theory and Albrechtos theory is provided, and their connection and applications are discussed. The former is a first order perturbative theory on optical transitions intended for applications such as absorption and emission involving localized defect or impurity centers, emphasizing lattice relaxation or mixing of vibrational states due to electron–phonon coupling. The coupling strength is described by the Huang–Rhys factor. The latter theory is a second order perturbative theory on optical transitions intended for Raman scattering, and can in-principle include electron–phonon coupling in both electronic states and vibrational states. These two theories can potentially be connected through the common effect of lattice relaxation – non-orthonormal vibrational states associated with different electronic states. Because of this perceived connection, the latter theory is often used to explain resonant Raman scattering of LO phonons in bulk semiconductors and further used to describe the size dependence of electron–phonon coupling or Huang–Rhys factor in semiconductor nanostructures. Specifically, the A term in Albrechtos theory is often invoked to describe the multi-LO-phonon resonant Raman peaks in both bulk and nanostructured semiconductors in the literature, due to the misconception that a free-exciton could have a strong lattice relaxation. Without lattice relaxation, the A term will give rise to Rayleigh or elastic scattering. Lattice relaxation is only significant for highly localized defect or impurity states, and should be practically zero for either single particle states or free exciton states in a bulk semiconductor or for confined states in a semiconductor nanostructure that is not extremely small.