Bulk and impurity infrared absorption in 0.5 As2Se30.5 GeSe2 glass

A study of infrared absorption in the 250–4000 cm^?1 region has been carried out for 0.5 As₂Se₃0.5 GeSe₂ glasses quantitatively doped with oxide impurity. The frequencies of the intrinsic 2- and 3-phonon absorption bands at 490 and 690 cm^?1 correspond well to those predicted from combinations of the high frequency bands in the first order IR and Raman spectra of As₂Se₃ and GeSe₂ glasses.Glasses doped with As₂O₃ exhibit the same oxide impurity absorptionbands as those doped with GeO₂. Unlike As₂Se₃ glass, at impurity concentrations up to 1000 ppm As₂O₃, 0.5 As₂Se₃0.5 GeSe₂ glass exhibits only one major oxide impurity species, characterized by absorption bands at 780 and 1260 cm^?1 and due to oxygen bonded to network Ge. The observation of a much weaker network AsO vibration band at 670 cm^?1 confirms that oxygen bonds preferentially to Ge in this glass. The same minor oxide species appears to determine excess IR absorption at the CO₂ laser wavelength of 10.6 μm in both As₂Se₃ and 0.5 As₂Se₃ 0.5 GeSe₂ glasses. The frequencies and intensities of absorption bands due to hydrogen impurities are also quite comparable for these two materials.