Optical properties of erbium doped tellurite glass with different NaCL composition

Abstract

A series of glasses based on (79.5-x)TeO2-20Na2O-(x)NaCl-0.5Er2O3 (where x = 0.0, 2.5, 5.0, 7.5 and 10.0 mol %) are successfully prepared by melt quenching technique. The amorphous nature of the glass have been characterized using X-ray Diffraction technique and the optical properties are characterized by means of UVVis- NIR and photoluminescence spectroscopy. The value of the optical band gap and the Urbach energy are calculated from the absorption edge data. The value of optical band gap lies between 2.99 eV and 3.13 eV for the indirect transition whereas the value of Urbach energy varies from 0.17 eV to 0.27 eV. From the luminescence spectrum, it is found that the luminescence emission spectra centered at 435 nm, 475 nm and 563 nm which assigned to the transition of 2H11/2, 4S3/2 and 4F9/2 to 4I15/2 respectively under 375 nm of excitation wavelength. Most properties observed to be dependent in a systematic manner on the NaCl content