Phonon sidebands of the optical spectrum for the defect structure GaN:C +O

Abstract

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. • Multi-phonon sidebands of the optical spectra for point defects in GaN are present. • Localized phonon modes associated with the defect structure are calculated by ab initio approach. • Multi-phonon sidebands could be served as the fingerprints for the defect structures.