Optical Properties of Erbium doped Molybdenum Tellurite Glasses

The glasses with the composition of xEr 2 O 3 -5AgCl- 15MoO 3 -(80-x) TeO 2 (x = 0, 0.5 and 1 mol%, named as SMT0, SMT1 and SMT2, respectively) were synthesized using conventional melt quenching method and their optical properties were investigated through UV-Visible spectrophotometer. Density and molar volume values of the glass samples were estimated, their values were found in the range from 5.52 to 5.64 g/cm 3 and 27.737 to 28.689 cm 3 , respectively. The UV absorption spectra were recorded at room temperature in the wavelength range 200-1100nm. From the absorption edge data, it is found that both the direct and indirect type transitions may takeplace. The direct and indirect band gap values are ranging from 1.92 to 2.29 eV and 1.24 to 1.77 eV, respectively. Also, the Urbach energy (E tail ) values were determined and their values are ranging from 0.33 to 0.54 eV. These obtained E tail values are well matched with amorphous semiconductors (0.046 to 0.66 eV)