Characterization of Cd1-x ZnxTe Alloys Using Infrared Reflectivity and Raman Scattering Spectroscopy

Study of impurity-induced phonon disordering in Cdl-xZnxTe alloys is reported for a variety of samples by using far-infrared reflectivity and Raman scattering spectroscopy. Substantial differences were noted among the various published values for the optical phonon frequencies versus x. Contrary to an earlier Raman study on MBE grown Cdl-xZnxTe/GaAs films, our results within a twomode behavior, yield an increase of both the CdTe- and ZnTe-like transverse optical phonons with x. Unlike earlier speculations for a gap-mode in ZnTe : Cd of ∼140∼145 cm−1, our Greens function theory predicts it to be at a relatively higher frequency of ∼153 cm−1.