Effect of CsI addition on the thermal properties, crystallization kinetics and short-wavelength absorption edges of GeSe2–Ga2Se3 glasses

The glasses of (1 − x)(11/16GeSe2–5/16Ga2Se3)–xCsI (x = 0.1, 0.2 and 0.3) were prepared by the melt quench technique. The thermal properties and crystallization kinetics of these glasses were investigated by the differential thermal analysis. It is found that the glass of x = 0.2 is the most stable and that the increase of CsI decreases the activity energy of glass transition Et and the activity energy of glass crystallization Ec. When evaluating the thermal stability of the studied glasses with Ec, the crystallization frequency factor K0 should be considered. The crystallization process of the x = 0.1 glass is determined by two-dimensional crystal growth, while that of the other two glasses is realized by three-dimensional crystal growth. Through analyzing the short-wavelength absorption edges of the glasses in detail, it can be concluded that the addition of CsI increases the Urbach energy Eu, optical energy Egopt and Tauch energy Eg, and that all of the short-wavelength absorption edges are dominated by the indirect transition.