Optical properties and band structure of ZnP₂-D₄⁸

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• 作者：I.G. Stamov^a ; N.N. Syrbu^b ; ^{sirbunn@yahoo.com" class="auth_mail} ; V.V. Zalamai^c
• 关键词：Refractive index ; Optical transmission and reflection spectra ; Kramers-Kronig relations ; Optical constants ; Excitons ; Band structure
• 刊名：Journal of Luminescence
• 出版年：May, 2014
• 年：2014
• 卷：149
• 期：Complete
• 页码：19-27
• 全文大小：2199 K

文摘

The emission lines of bound and free excitons and their phonon replicas were observed in the luminescence spectra of ZnP₂-D₄⁸ crystals doped with Mn, Sn, Cd and Sb measured at 10 K. The emission lines are described by the model of axial center levels. Models of the bands of the bound excitons with different axial centers (Mn, Sn, Cd and Sb) are presented. It was observed that the indirect transitions in the excitonic bands were nonpolarized and that the direct transitions were polarized. The minimal direct energy gaps in the polarization E鈭 are due to the allowed 袚₁鈫捫?sub>1 transitions, and the gaps in the polarization E鈯 are due to the 袚₂鈫捫?sub>1 transitions. The temperature shift coefficient of the bands gaps differs for different polarizations in the temperature interval from 2 to 10 K (螖E/螖T=3.5 meV/K and 1 meV/K for E鈭 and E鈯, respectively). The optical constants n, k, 蔚₁, 蔚_2, d²蔚₁/dE² and d²蔚₂/dE² were calculated for the energy interval 1.5-10 eV using the Kramers-Kronig analysis of measured reflection spectra. The features observed in these spectra were interpreted using two types theoretical calculations of band structure as optical transitions.