The effects of ZnCl2 and ErCl3 on the vibrational spectra and structure of tellurite glasses

A series of zinc tellurite glasses, containing up to 40 mol% ZnCl2 and doped with 1–10 mol% ErCl3, was prepared by melting and casting and their structure was analyzed by polarized Raman and variable incidence infrared reflection spectroscopies. Kramers–Kronig analysis of the infrared reflectivity led to the identification of the vibrational mode components. The Raman spectra are dominated by an intense, depolarized boson peak at ∼45 cm−1 and a high frequency, polarized peak at ∼767 cm−1. The introduction of ZnCl2 and ErCl3 modifiers led to a blue shift of the high frequency peak, while the intensity of the boson peak was found to increase continuously with the Er3+ content. It is shown that the erbium and zinc compounds both break TeOTe bonds, introducing non-bridging chlorine species, connected mostly to the zinc atoms.