Speaker
Description
Chalcogenide glasses are known as perspective materials of optoelectronics with a high optical transparency in the infrared region of telecommunication windows 3-5 and 8-12 μm. In this work, influence of composition on structural transitions and optical properties of chalcogenide glasses was studied by Raman technique. Obtained Raman spectra chalcogenide system Ge$_{4.5}$.As$_{14.5}$Se$_{81}$, Ge13.5As23.5Se63 and Ge18As28Se54, Ge27As37Se36, Ge30As40Se30 were analyzed using CoRa software. The Ge–Se vibrations in [GeSe4] tetrahedrons occurred at 193 cm–1. The As-Se vibration band generally occurs at around 230 cm–1. In the higher frequency region, there occurred a weak band at 250 cm–1 with a broad shoulder at 300 cm–1, assigned to Se–Se vibrations in Se-chains and asymmetric stretches in [GeSe4], respectively. The existence of Ge–Ge bonds is indicated by the shoulder occurring in the region 170–180 cm–1 at the lower frequency side of the Ge–Se band, assigned to Ge–Ge vibrations in [Se3Ge–GeSe3] structural units. The band at 100 cm–1 is assigned to As–As vibrations, and its shoulder at 130 cm–1 to Ge–As vibrations. As the content of germanium increases, the chance for tetrahedrons [GeSe4/2] meeting each other increases, which is indicated by the occurrence of edge-shared [GeSe4/2] band at 214 cm-1. Thus, the structure of the glasses is described as a mixture of the AsX3/2 and GeX 4/2 , connected either directly or through chalcogen chains and with presence of non-stoichiometric structural units.
| Topics | Session C. Applied optics and engineering |
|---|
