Role of S/Se ratio in chemical bonding of As-S-Se glasses investigated by Raman, x-ray photoelectron, and extended x-ray absorption fine structure spectroscopies

A systematic study on ternary As-S-Se glass, chalcogen-rich versus well-studied stochiometric compositions is carried out using Raman, x-ray photoelectron, and extended x-ray absorption fine structure spectroscopies. Results provide insight into the structural units and evidence for the existence of homopolar bonds that are the possible structural origin of the high nonlinearity in these glasses.