X-ray absorption fine structure study on the formation of Cu–Br bonds in (Br + Cu) ion implanted silica glass

The valence and coordination structure of implanted Cu and Br ions were investigated by x-ray absorption fine structure spectroscopy in (2.4 MeV 6 × 1016 Br2+ ions cm−2+ 2 MeV 6 × 1016 Cu+ ions cm−2)-implanted silica glass. It was found that the implanted Cu and Br atoms were coordinated by oxygen atoms and silicon atoms, respectively, in as-implanted glass. After heating at 600 °C, at least two-thirds of the Cu atoms were coordinated by Br atoms without the formation of crystals. The γCuBr crystal was formed after heating to 1100 °C. It was deduced that the coordination structure of Cu and Br atoms depends on defects as well as thermochemical stability and mass transport processes.