Effect of disorder on the Raman scattering of CdSxSe1−x films deposited by laser ablation

We present micro-Raman spectra at room temperature of CdSxSe1−x ternary films deposited on Si(111)-oriented substrates by means of the laser ablation technique. The lineshape of the LO phonon structure is characterized by significant asymmetry and broadening induced by disorder in the alloy. The asymmetric line profile can be described as a composite of two phonon modes, one ascribed to zone-center and the other to zone-edge phonons. Attempts to fit the experimental data to the spatial correlation model result in a poor agreement. We discuss the possibility to include into the lineshape analysis the contribution from the disorder-activated phonon density of states.