Effect of MnO on the optical band gap in MnO-CdO-P(2)0(5) glasses

Manganese cadmium phosphate glasses having a mole% composition x%MnO-[50 - x]%CdO-50% P2O5 were prepared by using the melt-quench technique. The quant ity x had values of 0 similar to 35. The mass density of these glasses was found to be in the range of 3.8207 similar to 3.1509 g/cm(3). The absorptio n spectra of these glasses were recorded in the UV-Visible range. No sharp edges were found in the optical spectra, which verified the amorphous natur e of the glasses. The optical band gap energies for the glasses were calcul ated using the Mott and Davis relation and were found to be in the range of 2.60 similar to 3.42 eV. It was observed that the optical band gap energy decreased with increasing manganese oxide. The band tailing, worked out fro m the Urbach plots, first decreased with MnO up to 20 mole% and then increa sed with increasing MnO content. The absorption coefficient showed an expon ential dependence-on the photos energies.