Temperature dependence of Raman scattering inZnO
Аннотация: We present a Raman scattering study of wurtzite $\mathrm{ZnO}$ over a temperature range from 80 to $750\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. Second-order Raman features are interpreted in the light of recent ab initio phonon density of states calculations. The temperature dependence of the Raman intensities allows the assignment of difference modes to be made unambiguously. Some weak, sharp Raman peaks are detected whose temperature dependence suggests they may be due to impurity modes. High-resolution spectra of the ${E}_{2}^{\mathrm{high}}$, ${A}_{1}(\mathrm{LO})$, and ${E}_{1}(\mathrm{LO})$ modes were recorded, and an analysis of the anharmonicity and lifetimes of these phonons is carried out. The ${E}_{2}^{\mathrm{high}}$ mode displays a visibly asymmetric line shape. This can be attributed to anharmonic interaction with transverse and longitudinal acoustic phonon combinations in the vicinity of the $K$ point, where the two-phonon density of states displays a sharp edge around the ${E}_{2}^{\mathrm{high}}$ frequency. The temperature dependence of the linewidth and frequency of the ${E}_{2}^{\mathrm{high}}$ mode is well described by a perturbation-theory renormalization of the harmonic ${E}_{2}^{\mathrm{high}}$ frequency resulting from the interaction with the acoustic two-phonon density of states. In contrast, the ${A}_{1}(\mathrm{LO})$ and ${E}_{1}(\mathrm{LO})$ frequencies lie in a region of nearly flat two-phonon density of states, and they exhibit a nearly symmetric Lorentzian line shape with a temperature dependence that is well accounted for by a dominating asymmetric decay channel.
Год издания: 2007
Авторы: R. Cuscó, Esther Alarcón‐Lladó, Jordi Ibáñez, L. Artús, J. Jiménez, Buguo Wang, Michael J. Callahan
Издательство: American Physical Society
Источник: Physical Review B
Ключевые слова: ZnO doping and properties, Perovskite Materials and Applications, Electronic and Structural Properties of Oxides
Открытый доступ: closed
Том: 75
Выпуск: 16