title: Elucidation of codoping effects on the solubility enhancement of Er3+ in SiO2 glass: striking difference between Al and P codoping.
abstract: The codoping effect mechanism of Al and P on the solubility enhancement of Er(3+) ion in SiO(2) glass was clarified by electron spin-echo envelope modulation spectroscopy. It turned out that doped P ions preferentially coordinate to the Er(3+) ion to form a "solvation shell structure", and the environment is similar to that in phosphate glass, while doped Al ions do not form such a selective solvation structure, taking octahedral coordination. This striking difference indicates that the primary roles of the P-doping and the Al-doping are attributed to "enthalpy of mixing" and to "entropy of mixing", respectively.
authors.affiliation: Frontier Collaborative Research Center, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Saitoh
authors.forename: Satoru
authors.initials: S
authors.lastname: Matsuishi
authors.forename: Choi
authors.initials: C
authors.lastname: Se-Weon
authors.forename: Junji
authors.initials: J
authors.lastname: Nishii
authors.forename: Masanori
authors.initials: M
authors.lastname: Oto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hirano
authors.forename: Hideo
authors.initials: H
authors.lastname: Hosono