Features of the optical absorption, phonon spectrum and glass transition in As-Se, As-Se-S, As-Se-Te chalcogenide semiconductors

The optical properties, phonon spectrum, amorphousness and glass transition temperature of As40Se60, As40Se30Te30, As40Se30S30, As33,3Se33,3S33,4, As33,3Se33,3Te33,4 chalcogenide glasses have been studied by optical, Raman spectroscopy, X-ray diffraction and differential scanning calorimetry (DSC) methods. Ithas been determined the values of optical band gap(Eg), energy of Urbach(U), the bands of Raman scattering, glass transition temperature(Tg) and also was calculated the parameters characterizing the amorphous matrix as cohesive energy(CE), the average bond energy (< E >) average coordination number(Z), the average value of the atomic volume (Va), packing density (x) and compactness (delta) in studied compositions. The results show that, there is correlation between the cohesive energy (CE), the glass transition temperature(Tg), the average bond energy (< E >) and the optical band gap (Eg).