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The Crystallization Effect on the Optical Properties of Oxyfluoride Glass-Ceramics Containing CaF2 Nanocrystals Doped with Y3+ Ions

نویسندگان

  • L. Farahinia Department of Materials Science and Engineering, University of Tabriz, Tabriz, Iran
  • M. Rezvani Department of Materials Science and Engineering, University of Tabriz, Tabriz, Iran

چکیده

In the present study, the oxyfluoride glasses of SiO2-Al2O3-CaF2 system containing different amounts of Y3+ ions were prepared through the convenient melting method. The crystallization temperatures and size of the CaF2 nanocrystals were obtained from DTA curves and XRD patterns, respectively. As a consequence, the optimum amount of Y2O3 dopant (0.5wt%) and the suitable composition for basic glass were determined from the viewpoints of better crystallization behavior and higher transparency. The FTIR spectra approved the presence of oxyfluoride glass-ceramic structure in samples. The optical parameters (Fermi energy level, Urbach energy, direct and indirect band gaps) were calculated using UV-Vis spectra. The decreasing trend of Fermi energy level for glass-ceramic samples crystallized at higher temperatures is related to better semiconducting behavior. Urbach energy and optical band gap of the glass-ceramic samples were reduced due to the increment of the structural order and the emergence of dangling bonds, respectively.

جستجوی کلمه کلیدی

band gap energy
Urbach tailing
Y2O3 dopant
Oxyfluoride glass

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