Glass formation, density, microhardness, and optical properties of As–Si–Te chalcogenide alloys

Abstract

The As–Si–Te glasses are IR transparent, have relatively high glass transition temperatures among the chalcogenide glasses, and thus have been considered suitable in high temperature IR-optical applications. Sixty one As–Si–Te alloys of various compositions were prepared, and their glass formation, glass transition temperatures, density, microhardness, and IR transmittance were experimentally determined. By quenching the As–Si–Te melt in air, glasses can be formed in the As–Si–Te system. Some of the as-quenched alloys are completely amorphous, and some are partially amorphous and partially crystalline. Most notably, some As–Si–Te alloys exhibit volatility. Although the As–Si–Te glasses have good IR transmittance, the oxygen impurities in the glasses cause IR absorption at the wave numbers of 690 cm −1 and 960 cm −1. Their glass transition temperature ( T g) decrease with Te contents, and the highest T g found in this study is at 394°C for the As 0.2Si 0.4Te 0.4. The densities of As–Si–Te alloys increase with higher silicon content. The microhardness of As–Si–Te alloys is relatively high among chalcogenide glasses and its value increases with increasing silicon content.