Infrared dielectric functions and phonon modes of wurtzite MgxZn1−xO (x⩽0.2)

Infrared dielectric function spectra and phonon modes with polarization parallel and perpendicular to the $c$ axis of high quality, highly relaxed, and single crystalline wurtzite ${\mathrm{Mg}}_x{\mathrm{Zn}}_{\text{1−x}}\mathrm{O}$ films with $\text{0⩽x⩽0.2}$ prepared by pulsed-laser deposition on $c$ -plane sapphire substrates were obtained from infrared spectroscopic ellipsometry (380–$\text{1200\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}})$ and Raman scattering studies. A two-mode behavior is found for the modes with $E_1$ symmetry, a lattice mode and an impurity-type mode are obtained for the $A_1$ symmetry phonons. Model dielectric function spectra will become useful for future infrared ellipsometry analysis of complex ${\mathrm{Mg}}_x{\mathrm{Zn}}_{\text{1−x}}\mathrm{O}$ -based heterostructures.