Structure And Optical Properties Of Ge(S_xSe_1-x)₄ And As₂(S_xSe_1-x)₃ Glasses

As a kind of important amorphous semiconductor materials,chalcogenide glass widely used in information storage,optical sensing,optical frequency conversion,signal transmission and other important areas,which has a broad development prospects.Ge(S_xSe_1-x)₄ and As₂(S_xSe_1-x)₃ glasses are two kinds of typical chalcogenide glasses.It has favorable thermal stability,chemical stability and complex microstructures.We could control the microstructure by controlling the composition and temperature in order to affects its performance.Consequently,a bridge between microstructure and performance is built.Therefore,the researches of the structure and optical properties of Ge(S_xSe_1-x)₄ and As₂(S_xSe_1-x)₃ glasses are significant.Glasses in Ge(S_xSe_1-x)₄ and As₂(S_xSe_1-x)₃ ternary system were prepared by the traditional melt-quenching method.Through the improvement firing system by rocking furnace,Ge(S_xSe_1-x)₄ and As₂(S_xSe_1-x)₃ glasses were gotten.The microstructure were studied by Raman spectra.The optical properties in visible-near infrared region were studied by UV-Vis-IR spectra measured by spectrophotometer and combined with the heating fittings at the same time,the relationship between optical band gap and temperature was studied.The refractive index dispersion was fitted by NKD and infrared spectroscopy.Based on the previous work,the microstructure of Ge(S_xSe_1-x)₄ and As₂(S_xSe_1-x)₃glasses is described detailedly.The micromechanism of the shift in Raman spectra is explained.It is determined and certified that the regularities of distribution of basic structure units is similar to chamical order random network model.The experimental results show that absorption edge shifts toward to lower frequency with the increase of temperature.It is inferred that the mod of electron transition in studied material is similar to the model of allowable indirect band gap transition.The electronic state density is gotten by XPS valence band spectra and computational EDOS.With the replacement of Se for S,optical band gap decreases quickly at first and subsequently slowly,which can be mainly ascribed to the shift of valence band maximum and conduction band minimum.With the elevation of temperature,the curves of the function of and photon energy shift to lower photon energy,.In low absorption region,the absorption in different temperature tends to be uniform.Defect mode,randomness and phonon may be the reason.