Chemical State and Refractive Index of Mg-Ion-Implanted Silica Glass

The chemical state of implanted Mg atoms has been studied in 2.48 ×1017 Mg+ ions cm-2-implanted silica glass by X-ray photoelectron spectroscopy. It was found that Mg atoms were coordinated with oxygen atoms, irrespective of the heat treatment at 900°C in an argon gas atmosphere. Mg ion implantation caused oxygen deficient species (SiOx) and increased the refractive index by about 5%. The oxygen deficient species and the refractive index change were stable against the heat treatment.