0000000000194978
AUTHOR
Hayato Kamioka
showing 6 related works from this author
Oxygen Exchange at the Internal Surface of AmorphousSiO2Studied by Photoluminescence of Isotopically Labeled Oxygen Molecules
2009
The exchange between lattice and interstitial oxygen species in an oxide was studied by the $^{16}\mathrm{O}\mathrm{\text{\ensuremath{-}}}^{18}\mathrm{O}$ isotope shift of the ${a}^{1}{\ensuremath{\Delta}}_{g}(v=0)\ensuremath{\rightarrow}{X}^{3}{\ensuremath{\Sigma}}_{g}^{\ensuremath{-}}(v=1)$ infrared photoluminescence band of the oxygen molecules (${\mathrm{O}}_{2}$) incorporated into the interstitial voids of amorphous ${\mathrm{SiO}}_{2}$ ($a\mathrm{\text{\ensuremath{-}}}{\mathrm{SiO}}_{2}$) by thermal annealing in $^{18}\mathrm{O}_{2}$ gas. A large site to site variation of the oxygen exchange rate, originating from structural disorder of $a\mathrm{\text{\ensuremath{-}}}{\mathrm{SiO}}_{…
Diffusion of oxygen molecules in fluorine-doped amorphous SiO2
2010
Abstract Effects of fluorine doping on the diffusion of interstitial oxygen molecules (O2) in amorphous SiO2 (a-SiO2) were compared to those obtained from a-SiO2 containing SiOH groups. Incorporation of moderate concentration ( ∼ 1 0 19 cm−3) of SiF groups gives rise to minor changes in diffusion parameters between 800 and 1100 ° C: only a slight decrease in solubility and an increase in the activation energy for diffusion can be detected. Incorporation of SiOH groups has similar weak effects on the solubility and activation energy for diffusion. These minor changes are most likely due to the enhancement of the flexibility of local Si–O network as a result of the dissociation of the netwo…
Exchange between interstitial oxygen molecules and network oxygen atoms in amorphousSiO2studied byO18isotope labeling and infrared photoluminescence …
2011
Amorphous ${\mathrm{SiO}}_{2}$ ($a$-${\mathrm{SiO}}_{2}$) thermally annealed in an oxygen atmosphere incorporates oxygen molecules (O${}_{2}$) in interstitial voids. When the thermal annealing is performed in $^{18}\mathrm{O}$${}_{2}$ gas, interstitial $^{18}\mathrm{O}$${}_{2}$ as well as interstitial $^{16}\mathrm{O}$$^{18}\mathrm{O}$ and $^{16}\mathrm{O}$${}_{2}$ are formed due to the oxygen exchange with the $a$-${\mathrm{SiO}}_{2}$ network. The ${a}^{1}{\ensuremath{\Delta}}_{g}(v=0)\ensuremath{\rightarrow}{X}^{3}{\ensuremath{\Sigma}}_{g}^{\ensuremath{-}}(v=1)$ infrared photoluminescence band of interstitial ${\mathrm{O}}_{2}$ was utilized to quantitatively analyze the oxygen exchange, t…
Isotope Effect on the Infrared Photoluminescence Decay of Interstitial Oxygen Molecules in Amorphous SiO2
2009
The decay constants of the a1Δg(v=0)→X3Σg-(v=0) infrared photoluminescence (PL) of isotopically-labeled oxygen molecules 16O18O and 18O2 dissolved in the interstitial voids of a-SiO2 are ~1.7 and ~2.5 times larger than that of 16O2. This difference originates from the isotope shift in the energy of the nonradiative transitions from the a state to the vibronic levels of the X ground state. Calibration of the PL quantum yield using the measured decay constants is essential to measure the correct concentration of isotopically-labeled interstitial O2.
Diffusion and reactions of interstitial oxygen species in amorphous SiO2: A review
2008
This article briefly summarizes the diffusion and reactions of interstitial oxygen species in amorphous SiO 2 (a-SiO 2 ). The most common form of interstitial oxygen species is oxygen molecule (O 2 ), which is sensitively detectable via its characteristic infrared photoluminescence (PL) at 1272 nm. The PL observation of interstitial 0 2 provides key data to verify various processes related to interstitial oxygen species: the dominant role of interstitial O 2 in long-range oxygen transport in a-SiO 2 ; formation of the Frenkel defect pair (Si-Si bond and interstitial oxygen atom, 0°) by dense electronic excitation; efficient photolysis of interstitial O 2 into O° with F 2 laser light (λ= 157…
Spontaneous oxygen loading into SiO2 glass by thermal anneal
2004
The interstitial oxygen molecules (O 2 ) in SiO 2 glass were detected down to ∼10 15 cm -3 by photoluminescence of O 2 at 1272nm excited at 765nm by a continuous-wave titanium sapphire laser. It was evidenced that SiO 2 glass thermally annealed in air between 800 and 1100°C spontaneously absorbs ∼10 16 cm -3 of O 2 from the ambient atmosphere. The time-dependent concentration change of the interstitial O 2 allows the determination of both the diffusion coefficient and the solubility of the interstitial O 2 .