Raman studies of vitreous Si<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>versus fictive temperature

Geissberger, A.E.; Galeener, F. L.

doi:10.1103/physrevb.28.3266

Cited by 366 publications

(185 citation statements)

References 11 publications

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“…The concentration of such a strained bond is as low as ³1% estimated from the Raman spectral data. 111) This explains well why a small amount of fluorine improves the vacuum-UV transmittance. The same argument is valid for the codoping effects of P and Al to enhance the solubility of RE ion in silica glass melt.…”

Section: Perspectivementioning

confidence: 83%

Doping effects in amorphous oxides

Funabiki

Kamiya

Hosono

2012

J. Ceram. Soc. Japan

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Impurity doping of crystalline Si is one of the most striking techniques in semiconductor technology. A rigid and perfect crystalline lattice is prerequisite for effective doping. However, it has been reported to date that introducing a small amount of impurities drastically improves also the properties of amorphous materials. This paper reviews three pronounced doping effects on optical and electrical properties of amorphous oxides; i.e., (i) F-doping of silica glass to improve the vacuum-ultraviolet optical transmission and radiation toughness, (ii) codoping effects on solubility enhancement of rare earth ions in silica glass melt, and (iii) electron-carrier generation in transparent amorphous oxide semiconductors. It is emphasized that effectiveness of electron doping is determined by the magnitude of electron affinity and stabilization energy of a dopant. Importance of the local structure formed around a dopant ion and the location of conduction band minimum measured from the vacuum level is addressed to understand the doping effects in amorphous oxides.

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Section: Perspectivementioning

confidence: 83%

Doping effects in amorphous oxides

Funabiki

Kamiya

Hosono

2012

J. Ceram. Soc. Japan

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“…D 1 and D 2 FWHM were allowed to vary between 20 and 40 cm -1 , respectively. Our fitting procedure in this region reproduces properly the baseline that Geissberger and Galeener [15] extracted for the D 2 defect band using a French curve. An illustration of the fitting result is given in Fig.…”

Section: Ion-irradiated Samplesmentioning

confidence: 96%

“…Many of the works concerning ion irradiations in silica are related to the changes induced by irradiation, namely densification effects [2], modifications in optical properties (refractive index [3], ionoluminescence [4,5], optical [6,7,8,9] and infrared [7,10,11,12,13] absorption and reflectance [14], Raman scattering [10,15,16]), mechanical properties (near-surface hardness [16,17], compaction and plastic flow [18]), chemical stability [19] and etching rate of the irradiated surfaces [1,3,6]. From these works it is concluded that microscopic and macroscopic structural modifications can both saturate at some lattice damage level depending on the density of deposited energy [3].…”

Section: Introductionmentioning

confidence: 99%

Raman measurements in silica glasses irradiated with energetic ions

Saavedra

León

Martin

et al. 2014

AIP Conference Proceedings

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Raman spectroscopic investigation of the structure of silicate glasses. III. Raman intensities and structural units in sodium silicate glasses The Journal of Chemical Physics 75, 3226 (1981) es ‡ Present address: Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), UMR CNRS-UPS 8182, Université de Paris Sud, 91405 Orsay Cedex, FranceAbstract. Ion irradiation with energetic He + (2.5 MeV), O 4+ (13.5 MeV), Si 4+ (24.4 MeV) and Cu 7+ (32.6 MeV) species at several fluences (from 5 x 10 12 to 1.65 x 10 15 ion/cm 2 ) were performed in three types of SiO 2 glasses with different OH content (KU1, KS-4V and Infrasil 301). After ion implantation the Raman spectra were measured and compared with the spectra of unirradiated samples. Irradiated samples of the three fused silica grades exhibit changes in the broad and asymmetric R-band (ω 1 around 445 cm -1 ), in D 1 (490 cm -1 ) and D 2 (605 cm -1 ) bands associated to small-membered rings. The D 2 band shows an increase with increasing fluences for different ions, indicating structural changes. Raman spectra of ion-irradiated samples were compared with the spectra of neutron irradiated samples at fluences 10 17 n/cm 2 and 10 18 n/cm 2 . Macroscopic surface cracking was detected, mainly at fluences corresponding to deposited energies between 10 23 eV/cm 3 and 10 24 eV/cm 3 (after ion beam shutdown).

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“…We chose to show these spectra because they cover the whole range of possible average diameter and specific surface. We can see the bands associated with the vibrational modes of silica with a Raman shift lower than about 1200 cm -1 and the O 2 PL-band at 1538 cm -1 [8,[28][29][30][31][32][33]. The presence of this latter band tells us that in our samples there is an amount of intrinsic interstitial molecular oxygen decreasing on increasing the specific surface of nanoparticles [22].…”

Section: Resultsmentioning

confidence: 74%

Properties of HO 2 • radicals induced by γ-ray irradiation in silica nanoparticles

Buscarino

Melodia

Alessi

et al. 2014

Journal of Non-Crystalline Solids

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We report an experimental investigation on the effects of γ-ray irradiation in several types of silica nanoparticles previously loaded with O 2 molecules. They differ in specific surface and average diameter. By electron paramagnetic resonance (EPR) measurements we observe the generation of about 10 18 HO 2• /cm 3 interstitial radicals.These radicals are induced by reaction of interstitial O 2 molecules with radiolytic H atoms, as previously suggested for O 2 -loaded bulk a-SiO 2 samples. However, at variance with respect to bulk materials, our experimental evidences suggest a different generation process of HO 2 • radical. In fact, by a detailed study of samples exposed to D 2 O, our results prove that radiolytic hydrogen atoms reacting with O 2 to produce HO 2 • mainly arise from a radiation induced breaking of H 2 O molecules in the layers surrounding the nanoparticles or in the interstices. Also, by the correlation of HO 2 • paramagnetic centers concentration, determined by EPR measurements, and O 2 Raman/PL signal we further considered the issue of the direct estimation of the O 2 concentration in silica nanoparticles from Raman/PL spectra giving an independent conversion factor (the ratio between these latter two quantities), which is in good agreement with those previously proposed by other authors basing on optical measurements.

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Raman studies of vitreous SiO2versus fictive temperature

Cited by 366 publications

References 11 publications

Doping effects in amorphous oxides

Doping effects in amorphous oxides

Raman measurements in silica glasses irradiated with energetic ions

Properties of HO 2 • radicals induced by γ-ray irradiation in silica nanoparticles

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