OPTICAL-PROPERTIES OF SILVER-DOPED AS33S67

Spectral dependence of the linear optical parameters (index of refraction, absorption coefficient) of Ag-doped AS33S67 thin films in the visible and near infrared region is reported. The data are analysed on the basis of a single-effective-oscillator model proposed by Wemple and DiDomenico. It is found that the oscillator energy E0 scales with the optical gap E(g)opt and decreases with increasing silver content, while the oscillator strength E(d) increases at the same time. It is argued that this latter observation indicates an increase in the effective cation coordination in the system with increasing silver content.