title: Oxygen exchange at the internal surface of amorphous SiO2 studied by photoluminescence of isotopically labeled oxygen molecules.
abstract: The exchange between lattice and interstitial oxygen species in an oxide was studied by the 16O-18O isotope shift of the a1Deltag(v=0)-->X3Sigmag-(v=1) infrared photoluminescence band of the oxygen molecules (O2) incorporated into the interstitial voids of amorphous SiO2 (a-SiO2) by thermal annealing in 18O2 gas. A large site to site variation of the oxygen exchange rate, originating from structural disorder of a-SiO2, is found. The average exchange rate has an activation energy of approximately 2 eV, which is much larger than that for the diffusion of interstitial O2 (approximately 0.8-1.2 eV). The average exchange-free diffusion length of interstitial O2 exceeds approximately 1 microm below 900 degrees C, providing definite evidence that oxygen diffuses as interstitial molecules in a-SiO2.
authors.affiliation: Transparent Electro-Active Materials Project, ERATO-SORST, Japan Science and Technology Agency, in Frontier Research Center, S2-13, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan. kkaji@tmu.ac.jp
authors.forename: Koichi
authors.initials: K
authors.lastname: Kajihara
authors.forename: Taisuke
authors.initials: T
authors.lastname: Miura
authors.forename: Hayato
authors.initials: H
authors.lastname: Kamioka
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hirano
authors.forename: Linards
authors.initials: L
authors.lastname: Skuja
authors.forename: Hideo
authors.initials: H
authors.lastname: Hosono