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  • 1
    Electronic Resource
    Electronic Resource
    Quantum-dot size-distribution analysis and precipitation stages in semiconductor doped glasses (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 28-32 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The sequence of stages during precipitation of semiconductor (e.g., CdS, CdSe) clusters from supersaturated glasses exhibiting quantum-confinement effects was investigated. The rate of formation of nanometer-size "quantum dots'' distributed in a continuous glass matrix is critically determined by the time and temperature of the heat treatment given to the quenched glasses. The entire precipitation process was analyzed in terms of several decomposition stages: nucleation, normal growth, coalescence of quantum dots, and devitrification of the glass matrix itself. Experimental data obtained by differential thermal analysis were utilized to identify the heat-treatment temperature range associated with the precipitation stages. The size distribution of CdSe quantum-dot clusters was analyzed using our transmission electron microscopy data. The data of Ekimov et al. [Solid State Commun. 56, 921 (1975)] was reduced to time-temperature master plots useful for precipitating quantum dots of a given size in glasses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347130
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  • 2
    Electronic Resource
    Electronic Resource
    Glass formation in simple ionic systems via constant pressure molecular dynamics (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 7384-7394 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The utility of constant pressure molecular dynamics (MD) in studies of glass formation is demonstrated by choosing NaCl and ZnCl2 as examples of MX and MX2 salts. Rigid ion pair potentials have been used to model the two salts. Results of these simulations are in good agreement with general glass formation principles. The effect of the interatomic potential on the glass transition and the cooling rate on glass formation in both the salts is reported. The parameter characterizing the inertia of the borders of the MD simulation cell has a strong influence on the glass transition temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456218
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  • 3
    Electronic Resource
    Electronic Resource
    Fluorescence Spectroscopy of Color Centers Generated in Phosphate Glasses after Exposure to Femtosecond Laser Pulses (2002)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 85 (2002), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A confocal fluorescence microscopy setup was used to observe, in situ, spectral changes in phosphate glasses which were modified using 0.3 μJ of tightly focused 800 nm, 130 fs laser pulses. On 488 nm excitation, the modified glass shows a broad fluorescence centered at roughly 600 nm, which decays with prolonged exposure to the 488 nm light. The decay behavior is dependent on the 488 nm power, with a faster decay rate for higher powers. A mechanism whereby color centers, formed by the femtosecond pulses, fluoresce when excited by the 488 nm light and are simultaneously photobleached is proposed to explain the observed behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2002.tb00219.x
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  • 4
    Electronic Resource
    Electronic Resource
    Selenium molecules and their possible role in deep emission from glasses doped with selenide nanocrystals (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 1054-1057 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the observation of Raman scattering from a vibration mode with frequency of 320 cm−1 and its higher-order harmonics in silicate glasses doped with selenide semiconductor nanocrystals such as CdSe and ZnSe. Comparison with Raman spectra of glasses and alkali halides doped with Se suggests that these modes are caused by the presence of selenium molecules in the glasses. When excited in the blue and green by an Ar+ laser, glasses containing Se only are found to emit strong near-infrared luminescence whose peak and line shape are very similar to the so-called "deep emission'' observed frequently from selenide-doped glasses. Possible effects of Se molecules on the linear and nonlinear optical properties of glasses containing selenide nanocrystals are discussed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362840
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  • 5
    Electronic Resource
    Electronic Resource
    Real-time hot-stage high-voltage transmission electron microscopy precipitation of CdS nanocrystals in glasses: Experiment and theoretical analysis (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 4576-4580 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Hot-stage high-voltage (1.5 MeV) transmission electron microscopy was used to directly observe CdS nanocrystals precipitated in a silicate glass and a theoretical framework of nanocrystal coarsening kinetics more appropriate than the popularly used Lifshitz–Slyozov–Wagner theory was developed. Nanocrystallite nucleation and coarsening were monitored in situ by video taping of bright-field images of the edges of thin (less than 2 μm) glass fragments heated in the hot stage; crystallite size distribution was obtained from the taped experimental observations. The effects of electron-beam heating and diffusion out of the nanocrystals were included in developing the theoretical analysis of coarsening kinetics which were used, in turn, to interpret the experimental size distribution curves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357291
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  • 6
    Electronic Resource
    Electronic Resource
    Synthesis of gallium nitride quantum dots through reactive laser ablation (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 3122-3124 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Nanocrystalline GaN was synthesized through reactive laser ablation of gallium metal in a N2 atmosphere. X-ray diffraction, selected-area electron diffraction, and transmission electron microscopy measurements show that the GaN crystallites are as small as 2 nm in diameter, and follow a log-normal size distribution with a mean particle diameter of 12 nm. Size-selective photoluminescence and photoluminescence excitation spectroscopy reveal a continuous range of blueshifted band-edge emissions and absorptions starting from the bulk value for gallium nitride and continuing to below 300 nm. These results are consistent with a GaN particle size distribution that encompasses regions above and below the excitonic-Bohr radius of GaN, such that the GaN material shows combined bulk and quantum confined optical properties. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.119109
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  • 7
    Electronic Resource
    Electronic Resource
    Rutherford backscattering spectroscopy and electron microprobe analyses of argon gas trapped in alumina thin films (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 129-130 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: rf-sputtered aluminum oxide thin films were analyzed for argon content using electron microprobe analysis (EMPA). Standardless Rutherford backscattering spectroscopy was performed on several Al2O3 films, and these data were used as calibration standards in EMPA. EMPA performed at 10 keV with two separate film standards gave reproducible trends; the estimated error in the EMPA argon analysis was calculated to be ±0.8 wt. % at 10 keV and ±1.4 wt. % at 5 keV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101439
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  • 8
    Electronic Resource
    Electronic Resource
    Size selected silicon particles in sol-gel glass by centrifugal processing (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 2301-2307 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Centrifugal processing was used to induce size selectivity in Si particles suspended in a silica sol-gel precursor solution. A model was developed to describe Stokes settling of the silicon particles in the sol-gel medium whose viscosity increases exponentially with time eventually leading to hardening to a solid glassy material. An empirical modification to the theoretical model accounts for settling of particle agglomerates. Experimental results for polydisperse silicon particulates centrifuged in a sol-gel of tetraethyl orthosilicate catalyzed by phosphoric acid are reported; the particle size and spatial distribution in the gelled matrix are explained by the model. The utility of centrifugal processing to produce functionally graded materials and semiconductor nanostructures is discussed. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.366973
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis and luminescence of silicon remnants formed by truncated glassmelt-particle reaction (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 1648-1650 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have obtained nanometer sized silicon remnants sequestered in glass matrices by terminating the reaction of pure silicon powders dispersed in the viscous melt at a temperature of 1400 °C. Repeated use of this truncated melt-particle reaction process dilutes the amount and size of silicon remnants, and bulk samples containing nanosize silicon crystallites embedded in a glass matrix were eventually obtained. These quantum dot sized silicon-in-glass materials emit greenish luminescence with peak wavelengths from ≈480 to 530 nm, considerably shorter than the reddish luminescence (at about 700–850 nm) observed in porous silicon structures prepared by electrochemical etching techniques; upon complete digestion of Si particles by the melt, the luminescence peaks disappear. Since our silicon-in-glass preparation method does not involve etching, the origin of the luminescence is not likely to be due to Si-O-H compounds (e.g., siloxene) postulated recently. The location of the luminescence peaks and the observed silicon crystallite size suggest quantum confinement leading to a widened silicon band gap arising from remnants in the glass matrix smaller than the exciton diameter of bulk silicon (10 nm).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.110724
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  • 10
    Electronic Resource
    Electronic Resource
    Silicon wafer-to-wafer bonding at T〈200 °C with polymethylmethacrylate (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 65 (1994), S. 439-441 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A versatile method for low temperature (T〈200 °C) bonding of silicon and oxidized silicon wafers is reported using spun cast films of polymethylmethacrylate (PMMA) as the bonding material. The PMMA films are thermoplastic, transparent, dielectric, planarizing, and photopatternable. Bonding was achieved with both unpatterned and patterned, 1-μm-thick films. Tensile bond strengths of 3.12 MPa were typical (although the strongest bond had a strength of 5.85 MPa) and thin film stresses of 10 MPa (tensile) were measured. Photopatterned PMMA films exhibited approximately 14% lateral pattern smear after bonding.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.112326
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