We present a Raman scattering study of wurtzite $\mathrm{ZnO}$ over a temperature range from 80 to $750\mathrm{K}$. 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 $E_2^{\mathrm{high}}$, $A_1\left(\mathrm{LO}\right)$, and $E_1\left(\mathrm{LO}\right)$ 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 $A_1\left(\mathrm{LO}\right)$ and $E_1\left(\mathrm{LO}\right)$ 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.

We have studied LO phonon-plasmon coupled modes by means of Raman scattering in n-InP for carrier densities between $6\times {10}^{16}$ and $1\times {10}^{19}$ ${\mathrm{cm}}^{-3}.$ A line-shape theory based on the Lindhard-Mermin dielectric function that takes into account the nonparabolicity of the InP conduction band as well as temperature and finite wave-vector effects is used to fit the Raman spectra and extract accurate values of the electron density. The results obtained from the Lindhard-Mermin model are compared with the charge density determinations based on the Drude and the hydrodynamical models, and the approximations involved in these models are discussed.

We present a lattice-dynamics study of rocksalt cadmium oxide (CdO). We use Raman scattering to investigate a series of high-quality CdO epilayers grown on sapphire substrates by means of metal-organic vapor phase epitaxy. Two main features are found to dominate the Raman spectra of CdO: a sharp peak at $\sim 265{\text{cm}}^{-1}$ and a broad feature at $\sim 390{\text{cm}}^{-1}$ . To assign these and other weaker second-order features that appear in the Raman spectra, we have carried out an ab initio calculation of the phonon dispersion in CdO. From the calculated two-phonon density of states (PDOS) we tentatively assign the peak at $265{\text{cm}}^{-1}$ to a $2\text{TA}\left(L\right)$ mode. The broadband centered at $\sim 390{\text{cm}}^{-1}$ seems to reflect the high two-PDOS in the $300–450{\text{cm}}^{-1}$ spectral region.