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  • 1990-1994  (28)
  • 1985-1989  (12)
  • 1940-1944  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Anisotropic Nd–Fe–B thin-film magnets for milli-size motor : The 5th Joint MMM−Intermag Conference (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 6627-6629 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Efforts were made to obtain anisotropic thin-film magnets at low substrate temperature. This is an important criterion for practical applications such as to build motors. The influence of substrate materials as well as film thickness on the c-axis orientation were studied. It has been shown that thin-film magnets with the easy axis of magnetization normal to the film plane could be deposited at a substrate temperature of around 450 °C by choosing the composition near the line from Nd13Fe76B11 to Nd13Fe70B17 in the ternary phase diagram. It was found that the anisotropic film magnets could be also deposited on the metallic substrate. The c-axis orientation tended to be isotropic with an increase in film thickness. The obtained results were used to fabricate a milli-size motor by depositing 20-μm-thick Nd–Fe–B films on a silicon steel disk substrate of 5-mm diam. The milli-size motor exhibited a torque of 0.8 g mm at a rotational speed of 3000 rpm.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.349879
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  • 2
    Digitale Medien
    Digitale Medien
    Transmission electron microscopic study of the ordered structure in GaInP/GaAs epitaxially grown by metalorganic chemical vapor deposition (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 2164-2166 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: GaInP epitaxial crystals grown on (001) GaAs at 660–700 °C by metalorganic chemical vapor deposition are examined by transmission electron microscopy. The computer-processed image of the high-resolution electron micrograph clearly reveals a lamellate-ordered domain structure of two variants of {111} superlattices, which is also investigated using cross-section and plan-view dark field electron micrographs. The spikes of well-defined superspots in the diffraction pattern were found to originate from the shape of the domains. The investigation of GaInP grown with different Zn concentrations showed that the disordering occurs as a result of a decrease in the density rather than the size of the domain.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.100287
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  • 3
    Digitale Medien
    Digitale Medien
    680-nm band GaInP/AlGaInP tapered stripe laser (1987)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 1572-1573 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A gain-guiding tapered stripe laser was fabricated using a Ga0.5In0.5P/(Al0.5Ga0.5)0.5In0.5P double heterostructure wafer grown by metalorganic chemical vapor deposition. The laser showed a continuous wave (cw) threshold current of 48 mA, a maximum temperature for cw operation of 81 °C, an aspect ratio of about 2, and an astigmatism near 25 μm. The emission wavelength was 684 nm. Thirty-two devices have been operating without significant degradation for more than 2000 h at 50 °C with a constant output power of 3 mW.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.98610
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  • 4
    Digitale Medien
    Digitale Medien
    Characterization of interfacial atomic steps in GaAs/AlAs superlattices by transmission electron microscopy (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 379-381 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have studied interfacial atomic steps in GaAs/AlAs superlattices using high-resolution transmission electron microscopy (HRTEM) and lattice image simulation. We find arrays of bright spots at the interface in the TEM image to be good indicators of the interface configuration. Doubling of the bright spot arrays and step-shaped arrays in TEM lattice images indicate a "type 1'' monolayer step whose front is perpendicular to the direction of the electron beam and a "type 2'' monolayer step whose front is parallel to the direction of the electron beam. Our HRTEM observations indicate that the atomic steps at GaAs and AlAs interfaces grown at 700 °C are denser than at interfaces grown at 500 °C.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.99899
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  • 5
    Digitale Medien
    Digitale Medien
    Thermal strain-induced degradation mechanism in the visible AlGaAs/GaAs laser (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 58 (1985), S. 2448-2452 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We fabricated and life-tested visible AlGaAs/GaAs channeled-substrate-planar-type lasers and found that some are degraded within 100 h of operation. We investigated these using photoluminescence and transmission electron microscopic images. The characteristic features in photoluminescence images are dark defects that run parallel to the channeled stripe. Using transmission electron microscopy, we found that these dark defects are composed of precipitates, dislocation loops, and dislocation dipoles. In order to know the relation between these degradation phenomena and the thermal strain induced by lattice mismatch, we calculated the stress distribution in the semiconductor laser using the finite element method. According to this simulation, a stress concentration in the active layer arises near the edges of the channeled stripe where the volume dilatation is maximal. Combining the results of experiments and simulation, we concluded that interstitial atoms created by nonradiative recombination migrate to the edges of the stripe, and that ultimately dark defects appear near the edges of the stripe.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.335919
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  • 6
    Digitale Medien
    Digitale Medien
    Low-threshold operation of hemispherical microcavity single-quantum-well lasers at 4 K (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 443-445 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We demonstrate low-threshold lasing at 4 K in optically pumped hemispherical In0.2Ga0.8As single-quantum-well microcavities. The incident threshold pump power density is 11 kW/cm2 corresponding to an absorbed power density of about 320 W/cm2, and the measured spontaneous emission factor β is about 0.01.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.108928
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  • 7
    Digitale Medien
    Digitale Medien
    Isoelectronic oxygen in II-VI semiconductors (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 60 (1992), S. 91-93 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The properties of isoelectronic oxygen in II-VI semiconductors were studied by photoluminescence measurements. It was found that oxygen in CdTe, CdS, and ZnS can act as an acceptor as well as in ZnSe, and that the acceptor levels of oxygen in CdTe, CdSe, and ZnS are shallower than those of typical acceptors such as Na. Charge transfer from the host lattice to the oxygen atom may play an important role in oxygen acting as an acceptor. Based on the charge-transfer model, it can be qualitatively interpreted that there are two roles of oxygen in II-VI compounds: acting as an acceptor or as a trap, and that they are classified by the ionicity of the compound. We also now understand better the chemical trend of the oxygen-acceptor levels becoming more shallow compared to the typical acceptors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.107385
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  • 8
    Digitale Medien
    Digitale Medien
    Sera from Patients with Multiple Sclerosis React with Human T-Cell Lymphotropic Virus-I GAG Proteins: Western Blotting and Solid-Phase Radioimmunoassay Analyses (1988)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 540 (1988), S. 0 
    Details
    ISSN: 1749-6632
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1749-6632.1988.tb27197.x
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  • 9
    Digitale Medien
    Digitale Medien
    The Regulation of Cholesteryl Ester Metabolism by 17β-Estradiol in Macrophages (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 748 (1994), S. 0 
    Details
    ISSN: 1749-6632
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Allgemeine Naturwissenschaft
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1749-6632.1994.tb17379.x
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  • 10
    Digitale Medien
    Digitale Medien
    Selenium and zinc doping in Ga0.5In0.5P and (Al0.5Ga0.5)0.5In0.5P grown by metalorganic chemical vapor deposition (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 5285-5289 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Electrical properties of Se- and Zn-doped Ga0.5In0.5P and (Al0.5Ga0.5)0.5In0.5P grown by atmospheric pressure metalorganic chemical vapor deposition under a wide range of growth conditions were investigated using van der Pauw–Hall measurements at room temperature. The dopants were hydrogen selenide and dimethylzinc. The samples were prepared so that parasitic conduction in the GaAs substrate just adjacent to the ternary or quaternary layers could be eliminated from the Hall measurement. The carrier concentration of GaInP and AlGaInP increased as the 0.8±0.1th power of the feed amount of dopants for both conductivity types. At a growth temperature around 680 °C, the hole concentration tended to saturate near the 1018 cm−3 level as the amount of dimethylzinc being fed increased. The carrier concentration decreased with increasing growth temperature, with apparent activation energies of 0.95 eV for Se doping and 1.9 eV for Zn doping. The group-V to group-III feed ratio had a weak influence on the carrier concentration. On the other hand, the Hall mobility of the layers grown under the various growth conditions remained almost constant: the electron mobilities of Se-Ga0.5In0.5P and Se-(Al0.5Ga0.5)0.5In0.5P within the carrier concentration range of 1017 〈n〈1018 cm−3 were 950–700 and ∼100 cm2/V s, respectively. The hole mobilities of Zn-Ga0.5In0.5P and Zn-(Al0.5Ga0.5)0.5In0.5P within the carrier concentration range of 1017 〈p〈1018 cm−3 were ∼34 and ∼16 cm2/V s, respectively.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.343718
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