Structure and bonding characteristics of chalcogenide glasses in the system BaSe Ga2Se3GeSe2

Abstract The structure of chalcogenide glasses in the system BaSe Ga 2 Se 3 GeSe 2 is investigated using a combination of Raman spectroscopy, 71 Ga and 77 Se NMR spectroscopy and neutron scattering. The results of these experiments, when taken together, indicate that the structure of these glasses consists primarily of a corner-shared network of (Ga/Ge)Se 4 tetrahedra with minor edge-sharing. Homopolar metal–metal bonds are detected in glasses even with BaSe:Ga 2 Se 3 > 1, implying violation of chemical order; however, such bonding is primarily limited to Ge atoms, in the form of Ge Ge bonds. A comparison between these glasses and crystalline Ba 2 GeSe 4 , of their Raman and NMR spectroscopic signatures, suggest the formation of a modified network with non-bridging Se atoms upon increasing the BaSe content. Therefore, the structure of BGGS glasses undergoes network modification characteristic of oxides as well as continuous alloying and homopolar bond formation characteristic of non-oxide chalcogenides.