0000000000162583

AUTHOR

C. Oproiu

showing 3 related works from this author

Structure of amorphous SiO 2 nanoparticles probed through the E′ γ centers

2011

We report an experimental investigation by electron paramagnetic resonance (EPR) spectroscopy on the properties of the E′ γ centers induced by β-ray irradiation in nanoparticles of amorphous SiO 2 (fumed silica) with mean diameters from 7 up to 40 nm. We found that the E′ γ centers are induced in all the fumed silica types in the dose range 4-400 kGy. They are characterized by an EPR line shape similar to that observed in common bulk silica materials independently on the particle diameter. Moreover, the E′ γ center concentration decreases on decreasing of the particle size for each given dose. Our findings are interpreted in terms of a shell-like model of nanoparticles in which it is assume…

Materials scienceElectronic Optical and Magnetic MaterialSettore FIS/01 - Fisica SperimentaleAnalytical chemistryNanoparticleSurfaces Coatings and FilmNanotechnologySurfaces Coatings and FilmsElectronic Optical and Magnetic Materialslaw.inventionAmorphous solidGeneral EnergyEnergy (all)lawParticle sizeIrradiationPhysical and Theoretical ChemistryElectron paramagnetic resonanceSpectroscopypoint defects silica nanoparticles electron paramagnetic resonanceRadiation resistanceFumed silica
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Comparison of γ and β-ray irradiation effects in sol-gel Ge-doped SiO<inf>2</inf>

2009

We report an experimental study on the comparison between the γ or β ray induced Ge related point defects in Ge doped silica. Silica samples doped with ∼2.2 1017 Ge atoms/cm3 produced with the sol-gel technique have been irradiated. The effects of the irradiation have been investigated by optical absorption, photoluminescence and electron paramagnetic resonance spectroscopy in order to evaluate the generation and the dependence on dose of the Ge(1), E'Ge, Germanium Lone Pair Center (GLPC) and H(II) point defects. No relevant differences between the concentrations of γ or β ray induced Ge(1) and E'Ge point defects have been observed. In addition, it is found that both irradiations are able t…

PhotoluminescenceMaterials sciencebusiness.industryDopingInfrared spectroscopychemistry.chemical_elementGermaniumCrystallographic defectchemistryPhysical chemistryOptoelectronicsIrradiationbusinessSpectroscopyLone pair2009 European Conference on Radiation and Its Effects on Components and Systems
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Formation of optically active oxygen deficient centers in Ge-doped SiO2 by γ- and β-ray irradiation

2010

Abstract We report an experimental study on the comparison between the γ- or β-ray induced Ge related point defects in Ge-doped silica. Silica samples doped with ∼2.2 1017 Ge atoms/cm3 produced with the sol–gel technique have been irradiated with γ-ray or with β-ray. The effects of the irradiation have been investigated by optical absorption, photoluminescence and electron paramagnetic resonance spectroscopy in order to evaluate the generation and the dependence on dose of the Ge(1), E’Ge, GLPC (Germanium lone pair center) and H(II) point defects. No relevant differences between the concentrations of γ- or β-ray induced Ge(1) and E’Ge point defects have been observed and, in addition, it ha…

PhotoluminescenceAbsorption spectroscopySettore FIS/01 - Fisica Sperimentalechemistry.chemical_elementGermaniumdifetti di punto in siliceCondensed Matter PhysicsCrystallographic defectElectronic Optical and Magnetic Materialslaw.inventionCrystallographychemistrylawMaterials ChemistryCeramics and CompositesIrradiationSpectroscopyElectron paramagnetic resonanceLone pairNuclear chemistryJournal of Non-Crystalline Solids
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