High Order Oxygen Local Vibrational Modes in ZnS1-xOx

Substitution of O in the ZnS lattice is observed to result in a doublet consisting of two local vibrational modes (LVMs) and a second order harmonic of the LVMs. The first order doublet is attributed to vibrational modes of a defect with trigonal (C-3v) symmetry. The results of temperature dependent resonant Raman scattering and anti-Stokes scattering support this assignment. The substitution of O in the lattice also leads to the presence of LVM + nLO combination modes, which are interpreted in terms of the cascade model and resonance effects.