Refractive index change dependence on Ge(1) defects in {gamma}-irradiated Ge-doped silica
- Department of Physical and Astronomical Sciences, University of Palermo, Via Archirafi 36, 90123 Palermo (Italy)
- Department of Physical Chemistry, University of Pavia, Via Taramelli 16, 27100 Pavia (Italy)
- Department of Nuclear Engineering, University of Palermo, Viale delle Scienze, Building 6, 90128 Palermo (Italy)
We present an experimental study regarding the effects of the {gamma} radiation on silica glass doped with Ge up to 10 000 ppm molar produced by the sol-gel technique. We have determined the irradiation-induced changes in the refractive index ({delta}n) as a function of the oxygen deficiency of the samples, evaluated from the ratio between the germanium lone pair centers (GLPC) and the Ge content. {delta}n at 1500 nm have been estimated using optical-absorption spectra in the range 1.5-6 eV. We have found that {delta}n is independent of Ge differences for GLPC/Ge values <10{sup -4}, while it depends on Ge for larger oxygen deficiencies. In details, the oxygen deficiency can reduce the induced {delta}n of the investigated materials and our studies evidence that the photosensitivity of the GeO{sub 2}-SiO{sub 2} glass is reduced until the GLPC concentration reaches values of 2x10{sup 17}-5x10{sup 17} defects/cm{sup 3}. We have also investigated the induced concentration of paramagnetic point defects [Ge(1), Ge(2), and E'Ge] using the electron-paramagnetic-resonance (EPR) technique. From the comparison of the optical and EPR data we have further found a relation between the induced optical-absorption coefficient at 5.8 eV and Ge(1) defects, a linear correlation between Ge(1) and {delta}n and the absence of a correlation between the other paramagnetic defects and {delta}n. These findings suggest that the {delta}n phenomenology is closely related to the Ge(1) generation mechanisms and this latter is affected by the oxygen defic0011ien.
- OSTI ID:
- 21308703
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 80, Issue 1; Other Information: DOI: 10.1103/PhysRevB.80.014103; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ABSORPTION
ABSORPTION SPECTRA
COMPARATIVE EVALUATIONS
DOPED MATERIALS
ELECTRON SPIN RESONANCE
GAMMA RADIATION
GERMANATES
GERMANIUM ADDITIONS
GERMANIUM OXIDES
GLASS
IRRADIATION
OXYGEN
PARAMAGNETISM
PHOTOSENSITIVITY
PHYSICAL RADIATION EFFECTS
POINT DEFECTS
REFRACTIVE INDEX
SILICA
SILICON OXIDES
SOL-GEL PROCESS
ULTRAVIOLET SPECTRA