Optical property evaluation of oxyfluoride glasses doped with different amounts of Y3 + ions

• Y3 + ions had a network former role in oxyfluoride glass network.
• FT-IR results approved Y3 + ions' network former role.
• Semiconducting behavior of the glass increased in the presence of Y2O3.
• Urbach energy decreased by increasing the amount of Y2O3.

In present study, oxyfluoride glasses doped with different amounts of Y2O3 (0.5, 1 and 1.5 wt.%) were prepared by the convenient melting process. Based on the density measurements and differential thermal analysis (DTA) results, the network-forming role of Y3 + ions was proved. In addition, Fourier transform infrared spectroscopy (FT-IR) study of the samples approved this claim by showing structural changes happening with the increase of Y2O3 content. Using the UV–Vis spectra, optical properties including Fermi energy level, direct and indirect optical band gaps and Urbach energy were determined. The mentioned optical properties were calculated using Fermi–Dirac distribution function, Tauc's plots and absorption coefficient diagrams, respectively. Increment of optical properties with the increase of Y2O3 content (i.e. decrease of Fermi energy level from 3.59 to 3.17 eV, indirect band gap from 3 to 2.79 eV and direct band gap from 3.57 to 3.42 eV) confirms the better semiconducting behavior. Moreover, Urbach energy decreased from 0.27 to 0.23 eV arising from the network forming role of Y3 + ions in the glass network.