Effect of Se on Structure and Electrical Properties of Ge-As-Te Glass

International audienceThe Ge-As-Te glass has a wide infrared transmission window range of 3-18 mu m, but its crystallization tendency is severe due to the metallicity of the Te atom, which limits its development in the mid- and far-infrared fields. In this work, the Se element was introduced to stabilize the Ge-As-Te glass. Some glasses with Delta T >= 150 degrees C have excellent thermal stability, indicating these glasses can be prepared in large sizes for industrialization. The Ge-As-Se-Te (GAST) glasses still have a wide infrared transmission window (3-18 mu m) and a high linear refractive index (3.2-3.6), indicating that the GAST glass is an ideal material for infrared optics. Raman spectra show that the main structural units for GAST glass are [GeTe4] tetrahedra, [AsTe3] pyramids, and [GeTe4Se4-x] tetrahedra, and with the decrease of Te content (<= 50 mol%), As-As and Ge-Ge homopolar bonds appear in the glass due to the non-stoichiometric ratio. The conductivity sigma of the studied GAST glasses decreases with the decrease of the Te content. The highest sigma value of 1.55 x 10(-5) S/cm is obtained in the glass with a high Te content. The activation energy E-a of the glass increases with the decrease of the Te content, indicating that the glass with a high Te content is more sensitive to temperature. This work provides a foundation for widening the application of GAST glass materials in the field of infrared optics