Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1990-1994  (22)
Source
Material
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Generation mechanisms of paramagnetic centers by gamma-ray irradiation at and near the Si/SiO2 interface (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 8519-8525 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Pb (⋅Si≡Si3) and E' (⋅Si≡O3) centers in the Si/SiO2 structure under gamma-ray radiation are studied with the electron-spin-resonance technique. The Si/SiO2 structures of (111), (110), and (100) planes are obtained using three different oxidation methods to control the concentration of the hydrogen-related impurities. It is first observed that the concentration of Pb centers is decreased with increasing radiation dosage in samples with lower concentrations of impurities; the concentration dramatically increases in the samples with a higher concentration of impurities. The concentration of E' centers also increases with accumulated dosage. When the Si/SiO2 structure is fabricated under different oxidation temperatures, the saturated concentrations of Pb centers after irradiation depend upon the oxidation temperature. The concentration of E' centers increases with oxidation temperature after irradiation. When the Si/SiO2 structure is fabricated under different cooling rates, concentrations of the Pb centers are saturated after irradiation. The concentration of E' centers increases with increasing cooling rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353380
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effects of oxidation conditions on the formation of paramagnetic centers at and near the Si/SiO2 interface (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 2979-2985 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: To discern the most important parameter determining the concentration of paramagnetic centers, the effects of chemical treatments before and/or after oxidation, the type of furnaces, the cooling rate after oxidation, and oxidation temperature were examined. The effects of chemical treatments for cleaning on Pb and E' centers before and/or after oxidation were negligible. Two types of furnaces were prepared: One where contamination by the outer air could be prevented and one where it could not be prevented, called an air-removed furnace and a conventional furnace, respectively. The concentration of Pb and E' centers at the Si/SiO2 interface fabricated in a conventional furnace was, however, drastically smaller than that fabricated in an air-removed furnace. The cooling rate after oxidation did not determine the concentration of E' centers but affected Pb centers. The oxidation temperature also determined the concentration of both Pb and E' centers. It was found that the parameter most effective in determining the concentration of paramagnetic centers was the type of furnace, whether there was contamination from air or not. The paramagnetic centers (such as Pb and E' centers) react with some element(s) in the air. It is expected that such elements are not N2 gas but hydrogen-related impurities in the air, perhaps H2O.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349325
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Simultaneous generation of the 7.6-eV optical absorption band and F2 molecule in fluorine doped silica glass under annealing (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 4183-4188 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We examined chemical state of fluorine doped silica glasses and its thermal behavior. Almost all of the fluorine atoms were found to have the ≡SiF structure with Raman spectroscopy. No optical absorption in the region of 3–9 eV was detected in the glass. When the glasses were annealed in a He atmosphere at 1000 °C, absorption bands peaking at 7.6 and 4.3 eV appeared. These two bands are attributed to the ≡SiSi≡ structure and to F2 molecules, respectively. We proposed a thermal decomposition reaction expressed as ≡SiF+FSi≡→≡SiSi≡+F2. The concentrations of the reaction products, ≡SiSi≡ and F2, estimated from the absorption cross sections were equal to each other within the errors of measurements. We also examined the radiation damage with γ ray. The concentration of E' center was almost the same for the same dose in silica glasses having different concentrations of FSi≡ and ≡SiSi≡. We suggest that FSi≡ and ≡SiSi≡ were found to be stable for γ-irradiation at room temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348386
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Optical properties of oxygen-deficient centers in silica glasses fabricated in H2 or vacuum ambient (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 69-74 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Silica soots were sintered under a reducing ambient to study the generation mechanism of the oxygen-deficient-type defects in silica glasses. Glasses sintered under H2/He gas mixtures or vacuum were prepared with an intent to produce oxygen-deficient centers. Two optical-absorption bands were generated in the silica glasses sintered under the H2/He gas mixtures. One was 5.17-eV absorption band and the other was an absorption tail near the Urbach tail of silica glasses. Both absorptions were attributed to the silicon lone pair center (SLPC). On the other hand, the other type of reduced silica glasses were prepared in the vacuum ambient. Three kinds of absorption bands could be detected clearly: one was peaking at 5.17 eV, another showed only its shoulder near the Urbach tail, (both were also attributed to the SLPC) and the third was peaking at 6.7 eV and was attributed to a SiSiSi structure. Fabricated in higher volatile ambient under vacuum, the color of the sample showed a smoky black and generated broad absorption band peaking at 5.1 eV. This band is tentatively attributed to the optical absorption due to excitation from the inner shell of silicon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350245
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Formation mechanism of hydrogen-associated defect with an 11.9 mT doublet in electron spin resonance and red luminescence in 9SiO2:GeO2 fibers (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 2237-2240 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The nature and the origin of the 11.9 mT hyperfine doublets in electron spin resonance spectrum observed in 9SiO2:GeO2 fibers were examined. When fibers were heated in hydrogen atmosphere at 100 °C, the intensity of the doublet increased. When gamma-ray irradiated, the intensity drastically increased. The photoluminescence bands peaking at 1.91 eV (650 nm) and 1.83 eV (680 nm) excited with Ar ion laser operated at 488 nm were also observed in the treated fibers with the doublets. It should be noted that the relation between the photoluminescence and the doublets was found. The intensities of the photoluminescence peaking at 1.83 eV and the 11.9 mT ESR doublets have accumulation. The germyl radical was proposed as their structural model. The origin of the photoluminescence peaking at 1.91 eV was tentatively proposed as the small silicon particles with hydrogen impurities generated in the fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354705
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Structural imperfections in silica glasses with an optical absorption peak at 3.8 eV (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 4696-4699 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Structural imperfections in silica glasses with an optical absorption peak at 3.8 eV were studied. The 3.8-eV peak was assigned to Cl2 molecules trapped in the glasses. The peak absorption was increased with increasing partial pressure of chlorine for sintering. The peak and its full width at half maxima were the same as those of Cl2 molecules in the gas phase. ≡SiOH was generated in the glasses by annealing in H2 ambient. After irradiation with a KrF excimer laser (5 eV), an absorption peak at 4.8 eV and red emission were observed. The properties were the same as the photochemical reaction of O2 molecules in the gas phase. We proposed that O2 molecules were trapped in the glass network when silica glasses were sintered under Cl2 ambient. The reaction is expressed as ≡SiOH+HOSi≡+Cl2→≡SiCl+ClSi≡+H2O↑+1/2O2 (trapped).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352358
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Characterization of silica glasses sintered under Cl2 ambients (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 1849-1852 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Chlorine incorporated into silica glasses by sintering porous soot rods under Cl2/He atmosphere or by fabricating with plasma methods were found to be mostly as ≡SiCl, which gives rise to an optical absorption tail above (approximately-equal-to)7.5 eV. The cross section of the optical absorption at (approximately-equal-to)7.77 eV (160 nm) was found to be 1.14×1020 cm2. This value was almost the same as that of ≡SiCl in SiCl4 molecule in the gas phase. A minor fraction (10−3∼10−1) was found to be present as Cl2 molecule, which gives the absorption band at 3.8 eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348753
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    O2 molecules dissolved in synthetic silica glasses and their photochemical reactions induced by ArF excimer laser radiation (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 3584-3591 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Silica glasses were prepared by three different techniques, vapor phase axial deposition method, oxidation of SiCl4 in O2-H2 flame, and O2 or O2-Ar plasma method with changing preparation conditions. This was done with the expectation that O2 molecules dissolve in the glasses with different concentrations by using a wide variety of preparation conditions. O2 molecules were found to be dissolved in the order of 1017 cm−3 and give an optical absorption above 7 eV, the so-called Schumann–Runge bands. The estimations of concentrations were done by using a molar absorption coefficient of ≡SiOH at 0.46 eV formed under a reaction of O2 with H2 diffusing from atmosphere at high temperature, 1/2 O2+H2+≡Si−O−Si≡ →2≡Si−OH. The concentration directly estimated from the absorption intensity at above 7 eV was consistent with those estimated from the IR band of ≡SiOH. On the ArF excimer laser irradiation of the glasses which possess the absorption band above 7 eV, the well-known absorption band at 4.8 eV was induced. This band was assigned to the Hartley bands of the O3 molecule. The reaction model was proposed to be O2(trapped)→2O(hν〉5.1 eV) and O+O2→O3(trapped). On exciting the induced 4.8 eV band, a photoluminescence at 1.9 eV was observed. The photoluminescence excitation spectrum of the band was agreed closely with the quantum yield curve of O(1D) on the excitation of Hartley bands of ozone. This suggests that the luminescence is due to the radiative relaxation of O(1D) to O(3P). The total reaction was proposed to be O3→O(1D)+O2 and O(1D)→O(3P)+1.9 eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346318
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Precursor to paramagnetic centers induced in gamma-irradiated doped silica glasses (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 1644-1649 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We prepared silica glasses having various concentrations of chlorine, fluorine, hydrogen (SiO2−x), and oxygen (SiO2+x) to examine the precursors of paramagnetic centers induced by γ rays. In the case of glasses sintered under chlorine and hydrogen ambients, the concentration of the E' center induced by γ-ray irradiation scaled with the partial pressure of chlorine and hydrogen. In contrast, the E' center was suppressed in glasses doped with fluorine. Stress in the glasses was also found to enhance formation of the E' center. Planar ring structures in the glass are influenced by stress and are proposed as precursors to the E' center.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353198
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Simultaneous generation of optical absorption bands at 5.14 and 0.452 eV in 9 SiO2 :GeO2 glasses heated under an H2 atmosphere (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 2713-2718 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Nine SiO2 :GeO2 glasses were heated under an H2 or O2 atmosphere. In the H2 atmosphere optical absorption bands were induced at vacuum ultraviolet (VUV) (〉6.22 eV), 5.14 eV (242 nm), 3.82 eV (325 nm), and 0.452 eV (2.75 μm). The intensities of all the induced bands are in linear relation with each other. Heat treatment in the O2 ambient reduced the intensities of the optical absorption bands. A model for the reaction of the glasses with H2 molecules and a structural model of the center responsible for the UV-VUV absorption was proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346445
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...