The passivation by diffusing H2 of silicon dangling bond defects (E′ centers, O3tSi•) induced by laserirradiation in amorphous SiO2 (silica) is investigated in situ at several temperatures. It is found that the reactionbetween the E′ center and H2 requires an activation energy of 0.39 eV and that its kinetics is not diffusionlimited.The results are compared with previous findings on the other fundamental paramagnetic point defectin silica, the oxygen dangling bond, which features completely different reaction properties with H2.Furthermore, a comparison is proposed with literature data on the reaction properties of surface E′ centers,of E′ centers embedded in silica films, and with theoretical calculations. In particular, the close agreementwith the reaction properties of surface E′ centers with H2 leads to the conclusion that the bulk and surface E′varieties are indistinguishable from their reaction properties with molecular hydrogen.
|Numero di pagine||5|
|Rivista||JOURNAL OF PHYSICAL CHEMISTRY. C|
|Stato di pubblicazione||Published - 2007|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films