We investigate the multi-phonon sidebands of the optical spectra of point defects in GaN based on the Huang-Rhys model, in which the localized phonon modes and the reorganization energy associated with the defect structure GaN: C_N + O_N are precisely calculated by ab initio approach. We present multi-phonon sidebands for both the localized phonon modes and intrinsic longitudinal optical phonon modes and give the comparisons between them in detail. Meanwhile, different types of the combinational phonon sidebands that are consisted of two localized phonon modes with different proportions are proposed. These multi-phonon sidebands not only could be used for the analysis of fine structure of the optical spectra, but also served as the fingerprints for the defect structures.

我们研究了基于 Huang-Rhys 模型的 GaN 中点缺陷光谱的多声子边带，其中局部声子模式和与缺陷结构 GaN:C _N  + O _N相关的重组能量由下式精确计算从头开始方法。我们提出了局部声子模式和固有纵向光学声子模式的多声子边带，并详细比较了它们。同时，提出了由两种不同比例的局域声子模组成的不同类型的组合声子边带。这些多声子边带不仅可以用于光谱精细结构的分析，还可以作为缺陷结构的指纹。