Infrared and Raman spectroscopic study ofZn1−xMnxSematerials grown by molecular-beam epitaxy

Abstract

Molecular beam epitaxy and optical investigation of ${\mathrm{Zn}}_{1-x}{\mathrm{Mn}}_x\mathrm{Se}$ epilayers over a large composition range $(x=0\mathrm{}–0.78),$ grown on GaAs (001) substrates, are reported. The far-infrared (FIR) reflectance and Raman scattering were performed to characterize the film quality and study their optical and electrical properties. FIR and Raman data provide experimental evidence on the intermediate-mode phonon behavior for ${\mathrm{Zn}}_{1-x}{\mathrm{Mn}}_x\mathrm{Se}$ with x up to 0.78. Theoretical modeling fits of FIR spectra lead to the determination of optical parameters such as mode frequency, strength, damping constant, and electrical properties of dielectric constant, carrier concentration, mobility, conductivity, and effect mass, and their dependence on the Mn composition. Values of force constants of $F_{\mathrm{MnSe}}=17.1\mathrm{}\times {10}^4{\mathrm{dyn}\mathrm{}\mathrm{cm}}^1$ and $F_{\mathrm{ZnSe}}=14.7\mathrm{}\times {10}^4{\mathrm{dyn}\mathrm{}\mathrm{cm}}^{\mathrm{-}1},$ and the high-frequency limit dielectric constant of MnSe, ${\epsilon }_{\infty }=5.4,$ are obtained.