Lattice dynamics of CdS/ZnSe strained layer superlattices studied by Raman scattering

We report on the lattice dynamical properties of cubic CdS/ZnSe strained-layer superlattices, investigated by means of Raman scattering. Folded acoustic phonons, confined optical phonons and a Zn-S interface vibration, which is a result of the AB/CD structure of the investigated heterostructure, are observed. The interpretation of the observed modes as an interface mode and contined ZnSe and CdS optical vibrations is supported by the behavior of multiple (two) LO-phonon scattering. The experimental results are compared with model calculations. Here the Rytov model is applied for the folded acoustic phonons. The frequencies of the confined optical phonons are described by the linear-chain model, while their intensities are compared with the hondpolarizability model. The agreement between these model calculations and the experimental observations is very good.