Optical Characterization of BK7 Borosilicate Glasses Containing Different Amounts of CeO_2

Borosilicate BK7 glasses doped with different amounts of CeO_2 (0.5, 1, 1.5%) were prepared by the convenient melting process. To study structural changes of samples, Fourier Transfer Infrared (FT- IR) and Raman spectroscopy were employed. The Differential Thermal Analysis (DTA) results exhibited addition of 0.5% cerium oxide has reduced T_g and also, according to the Urbach energy calculations, has made an enhancement in the disorderness of the glass network. Actually by increasing NBOs, CeO_2 played a glass modifier role. However, by adding 0.5-1.5% CeO_2, T_g increase and Urbach energy decrease could be the results of CeO_2 network former role. The calculation of direct/indirect band gap energy and Fermi energy level also indicated that by increasing the amount of dopant, the semiconducting characteristic of the glass became highlighted.