Manifestation of defects in phonon spectra of binary zinc-blende compounds

It is interesting to consider the problem of the presence of defects in the semiconductor binary compounds by observing their elemental tetrahedron distortions, caused by the creation of vacancies and interstitial atoms within the tetrahedra and so on. Our model thus considers the system A(Vz(x)Z(1-x)) and (A(1-y)Va(y))Z as composed of five defect tetrahedron configurations where A is a cation atom, Z an anion atom, V-alpha-cation vacancy, V-z-anion vacancy. In this communication we present far IR (FIR) spectra obtained at the DAFNE facility of Laboratori Nazionali di Frascati (INFN) using its synchrotron radiation. Two samples of CdTe are considered: sample-1 was grown by the PVT technique and sample-2 using the same technique but on the basis of, polycrystalline CdTe previously purified from oxygen in hydrogen atmosphere.