Optical Band Gap Studies on Dy~(3+) Doped Boro-Tellurite Glasses

摘要

The Dy~(3+) doped boro-tellurite glasses were prepared following conventional melt quenching technique with the chemical composition (69-x) H_3BO_3 + xTeO_2 + 15Mg_2CO_3 +15K_2CO_3 + 1Dy_2O_3 (where x = 0, 10, 20, 30 and 40 wt%). The optical absorption spectra have been recorded at room temperature to explore the optical properties. The optical band gap energy has been calculated using Davis and Mott theory through direct allowed, indirect allowed, and indirect forbidden transitions. Through the optical absorption spectra, optical band gap (E_(opt)), band tailing parameter (B), and Urbach energy (△E) were calculated for all the prepared glasses and the results were reported. It is observed from the results that the band gap energy value decreases, whereas Urbach's energy increases with the increase in TeO_2 content.