Fourier Transform Infrared Spectroscopy and Optical Properties of Samarium Doped Zinc Borotellurite Glasses

Zinc borotellurite glasses doped with Sm³⁺ ions of the (70-x)TeO₂-20B₂O₃-10ZnO-xSm₂O₃ system were prepared by a melt-quenching technique. The values of x varied from 0.0 mol% to 2.5 mol%. The studies on structural and optical characterisation of Sm³⁺ ions were carried out through Fourier transform infrared spectroscopy (FTIR), absorption spectra, optical band gap (Eopt) and Urbach energy (ΔE) analysis were presented for Sm³⁺ ions in zinc borotellurite glasses. From the FTIR analysis, the presence of BO₃, BO₄, TeO₃, TeO₄ and B - O - structural units in the prepared glasses was investigated. Three strong absorption peaks in the ultraviolet and visible regions were observed from absorption spectra due to transition between the ground state and various excited state of Sm³⁺ ions. The value of optical band gap, E_opt laid between 2.605 eV to 2.982 eV for the direct transition, and 2.768 eV to 3.198 eV for indirect transition, respectively. Meanwhile, the Urbach energy (ΔE) was observed in the range of 0.112 eV to 0.694 eV, respectively. Some other results were analysed and discussed in details. (author)