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  • 1
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 57 (2001), S. o416-o418 
    ISSN: 1600-5368
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The title 17-crown-5 unit, C24H24O5, comprising three benzo groups and diethylene glycol was prepared from the reaction of α,α′-dibromo-o-xylene and bisphenol in the presence of sodium hydride as base. This molecule offers a cavity suitable for host–guest complexes.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 5940-5945 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The crystallinity of lithium cobalt oxide thin films deposited by the radio-frequency (rf) reactive magnetron sputtering method has been improved by the rf plasma irradiation method. Compared with conventional thermal annealing, reaction to form crystalline lithium cobalt oxide via rf plasma irradiation is fast and does not need any additional external heat supply. It is found that the nucleation and the growth reactions are determined during the film deposition and the rf irradiation, respectively. The film composition does not change significantly, and severe mechanical damages such as resputtering or etching phenomena do not appear after the irradiation. A model showing the process of the crystallization by rf plasma irradiation is suggested on the basis of phenomenological analyses using secondary electron microscopy, high-resolution transmission electron microscopy, etc. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 3660-3666 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Highly oriented diamond particles are deposited on mirror-polished (100) silicon substrates in a bell-jar-type microwave plasma deposition system using a three-step process consisting of carburization, bias-enhanced nucleation and growth. By adjusting the geometry of the substrate and substrate holder, very dense disk-shaped plasma is formed over the substrate when the bias voltage is below −200 V. This dense plasma is a prerequisite for the high orientation and is not obtained simply by increasing microwave power, but is obtained by introducing a graphite block between the substrate and the substrate holder. The plasma is concentrated over the substrate with a thickness of several millimeters. From the results of the optical emission spectra of the disk-shaped dense plasma, it is found that the concentrations of atomic hydrogen and hydrocarbon radicals are increased with negative bias voltage. It is also found that the highly oriented diamonds are deposited in the region, where the intensity ratios of carbonaceous species to atomic hydrogen are saturated. As a result, it is suggested that the highly oriented diamonds are obtained by a combination of the high dose of carbonaceous species and the increased hydrogen etching effects. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 5246-5252 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Films of hydrogenated amorphous silicon carbide (a-SiC:H) have been prepared by a glow discharge decomposition from gas mixtures of C3H8-SiH4-H2 and CH4-SiH4-H2, in order to examine the effect of hydrocarbon gases on the structural and optical properties of these films. To study the influence of hydrogen on those properties of the propane-based films, the properties of the films deposited at different substrate temperatures (Ts) are systematically investigated using infrared (IR) and ultraviolet-visible absorption spectroscopies. By observing the change of intensities of IR absorption peaks with substrate temperature, the hydrogen bonding responsible for the absorption peaks could be assigned more accurately. When Ts is increased up to 300 °C, intensities of CH3 and SiH2 groups are reduced, indicating the formation of a dense network structure. At the same carbon concentration in gas mixtures, propane allows more carbon and hydrogen atoms to be effectively incorporated into the film than methane. The IR spectra reveal that the structure of a propane-based film has the characteristics of that of two kinds of films, methane- and ethylene-based films. It is found that the chemical bonding nature of the hydrocarbon gas strongly affects the bonding structure and the composition of the films. From these results, it is proposed that the use of propane is suitable for the fabrication of high-quality a-SiC:H with a wide optical gap ((approximately-greater-than)2.0 eV) and a deposition rate of ∼2 A(ring)/s.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 1275-1278 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: X-ray diffraction and observations of phase separation are reported in a hydrogen-induced amorphous ErNi2 alloy. Two separate diffuse maxima in x-ray diffraction and two principal halos in electron diffraction, which are evidence of phase separation into two amorphous states, are observed at hydrogenation conditions of 50 atm H2 and elevated temperatures. The phenomenon of phase separation is manifest with increasing hydrogenation temperature. The compositions of both phases are estimated by comparing the nearest-neighbor distances calculated by using the Ehrenfest relation with all possible atomic distances in amorphous ErNi2 hydride. These distances are calculated by assuming that the configurational atomic arrangement in the amorphous phase is composed of tetrahedral units. The compositions of the two phases seem to correspond to an Er-rich phase (mixture of 4-Er and 3Er+1Ni tetrahedra) and a Ni-rich phase (mixture of 4-Ni and 1Er+3Ni tetrahedra). This phase separation may be caused by the motion of Ni atoms over short distances.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 2618-2622 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Synthetic diamond film has been deposited on a polycrystalline titanium substrate using a hot-filament chemical vapor deposition method in order to study the role of substrate pretreatment and carbide formation for the diamond nucleation and subsequent growth. The substrate pretreatment, roughening by diamond powder, affects both nucleation behavior and subsequent growth of diamond. The TiC is formed on the Ti substrate during deposition. It is observed that scratches which existed on the initial Ti surface disappear after the TiC has formed; this TiC has a rough and porous structure. The TiC layer formed in this experimental condition does not influence the nucleation behavior. The nucleation behavior depends entirely on the initial surface condition of the Ti substrate, i.e., whether or not it was scratched with the diamond powder. It is suggested that changes in the surface nature due to the scratching process can create the new nucleation sites which have strong binding energies and that the formation of these new sites can alter the nucleation behavior.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 8329-8335 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The growth kinetics of diamond film has been studied, grown by a hot-filament chemical vapor deposition method, to obtain a fundamental information for the growth process of diamond from the gas phase. In order to study the growth kinetics of a pure diamond, the deposition conditions for high-quality diamond are first determined and the kinetics study is carried out under these deposition conditions. Diamond film thickness is directly proportional to the deposition time. This indicates that diamond films are deposited in the steady state under these experimental conditions. The variation of growth rate with substrate temperature shows a distinct maximum. The maximum temperature is shifted somewhat to the higher temperature side with increasing methane concentrations. It is found that this behavior is due to the decrease of supersaturation with increasing substrate temperature. However, the growth rate of diamond film increases linearly with methane concentrations. Therefore, the growth rate of diamond film can be described by the rate constant for a first-order reaction. From the kinetic data of diamond deposition, the deposition rate is controlled by the surface reaction (activation energy of 11 kcal/mol) at the lower temperature range, while the deposition rate is gas phase diffusion controlled (activation energy of 3.8 kcal/mol) at the higher temperature range.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 4272-4275 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The interfaces between diamond films and silicon substrate have been investigated to obtain a better understanding of the characteristics of diamond-substrate interface. In order to investigate the interface morphology, the backside surface of diamond film and the substrate surface have been observed after the deposited diamond film is separated from the silicon substrate. The vacant space between particles is found on the backside surface of the separated film and the central part of each particle caves in. Also, many of the hillocks are present on the Si substrate surface after the film is removed. From the observations, it is found that the interfaces between the diamond film and the silicon substrate is very rough. It is suggested that such interface morphology is attributed to the etching of the silicon substrate which takes place at the early stage of the synthesis. For the energy dispersive spectroscopy experiment of the backside surface of the separated film, more silicon is detected at the central part of each particle. This result implies that strong Si—C bonds are localized at the center of each particle, which would result in the poor adhesion.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 3354-3357 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Hot-filament-assisted chemical vapor deposition has been used to study the growth morphology of synthetic diamond deposited on silicon substrate in a dilute (1 vol %) CH3COCH3/H2 at high substrate temperature (about 777 °C). Scanning electron microscope pictures of the diamond particles show that the surfaces of synthetic diamond consist of rough-octahedral (111) faces and smooth-cubic (100) faces, which is cubo-octahedron. And also the (110) facets on the octahedral face are observed. The relative growth rate of (111) faces to that of (100) faces in the cubo-octahedron is double that derived from the calculated specific surface energy. So the apparent growth rate of the octahedral face must be explained by the growths of two constituent crystallographic planes of (100) and (110). The observed roughness of (111) faces arises from the competing growths of (100) and (110) planes. The (110) faces separate the (111) faces into three (110) planes. For the study of diamond crystal growth during deposition, it is suggested that the growth mechanism of cubo-octahedral diamond is the competing growths of (100) and (110) crystallographic planes.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 4758-4760 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of structural relaxation on hydrogen solubility in amorphous Pd80Si20 has been investigated by calorimetric and thermal desorption techniques. The hydrogen solubility is decreased by structural relaxation, an effect attributed to the elimination and redistribution of excess free volume quenched into the glass. As a result of structural relaxation, the width of site energy distribution decreases compared to that of the as-quenched state.
    Type of Medium: Electronic Resource
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