Search Results - (Author, Cooperation:M. Yoshikawa)

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  1. 1
    Staff View
    Publication Date:
    2018-06-14
    Publisher:
    The American Society for Microbiology (ASM)
    Print ISSN:
    0022-538X
    Electronic ISSN:
    1098-5514
    Topics:
    Medicine
    Published by:
    http://www.asm.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Staff View
    Publication Date:
    2011-08-27
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  3. 3
    Staff View
    Publication Date:
    2011-08-27
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  4. 4
    Staff View
    Publication Date:
    2011-08-27
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  5. 5
    Staff View
    Publication Date:
    2011-08-27
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  6. 6
    Staff View
    Publication Date:
    2018-02-28
    Publisher:
    Wiley-Blackwell
    Print ISSN:
    0148-0227
    Topics:
    Geosciences
    Physics
    Published by:
    http://www.wiley.com/wiley-blackwell

    Latest Papers from Table of Contents or Articles in Press
  7. 7
    Yoshikawa, M. ; Itoh, H. ; Morita, Y. ; Nashiyama, I. ; Misawa, S. ; Okumura, H. ; Yoshida, S.

    [S.l.] : American Institute of Physics (AIP)
    Published 1991
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Radiation effects on cubic silicon carbide (3C-SiC) metal-oxide-semiconductor (MOS) structures have been studied with high-frequency capacitance-voltage measurements. It was 〈m1;38p〉found that interface traps are generated at the 3C-SiC/SiO2 interface and oxide-trapped charges are built up in the oxide by 60Co gamma-ray irradiation. The generation of the interface traps and the oxide-trapped charges are affected by bias polarity applied to the gate electrode during the irradiation. Absorbed dose dependencies of their generation are discussed comparing with those of Si MOS structures.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.349587

    Articles: DFG German National Licenses
  8. 8
    Staff View
    ISSN:
    1089-7674
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    The improvement of potential confinement was attained in the GAMMA 10 tandem mirror [Phys. Rev. Lett. 55, 939 (1985); Proceedings of the 13th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Washington, 1990 (International Atomic Energy Agency, Vienna, 1991), Vol. 2, p. 539] by axisymmetrization of heating systems for the plasma production, heating, and potential formation. A significant increase of the density and diamagnetism by the potential confinement was observed. In the previous experiment, it was difficult to increase the central cell density higher than 2.7×1018 m−3. One of the possible mechanisms is the density clamping due to the eigenmode formation of the ion–cyclotron-range of frequency (ICRF) waves in the axial direction. With high harmonic ICRF waves (RF3), the experiments to overcome this problem have been performed. In preliminary experiments with RF3 and NBI the maximum density of 4×1018 m−3 was attained. © 2001 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1350962

    Articles: DFG German National Licenses
  9. 9
    Yoshikawa, M. ; Wagner, J. ; Obloh, H. ; Kunzer, M. ; Maier, M.

    [S.l.] : American Institute of Physics (AIP)
    Published 2000
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Resonant Raman scattering from AlxGa1−xN (x≤0.17) layers in (Al, Ga, In)N heterostructures has been studied using optical excitation at a photon energy of hνL=3.72 eV (333.61 nm). Tuning of the AlGaN band-gap energy, and thus of the resonance condition, was achieved by variation of the sample temperature. A pronounced outgoing resonance behavior was observed for first- and second-order Raman scattering by the AlGaN A1(LO) phonon, which allows a separation of the AlGaN LO phonon signal from the corresponding GaN phonon line even in the presence of much thicker surrounding GaN layers. The composition dependence of the AlxGa1−xN A1(LO) phonon mode was determined to ωLO(x)=734+356.8x−814.7x2 (cm−1) for the present excitation conditions (hνL=3.72 eV) and composition range (x≤0.17). The use of resonantly enhanced Raman scattering by the AlGaN A1(LO) phonon allowed us to assess nondestructively the composition of the AlGaN cladding layers in an (Al, Ga, In)N laser structure, even though the Raman spectrum recorded for nonresonant subband-gap excitation was completely dominated by scattering from the much thicker GaN layers in the structure. © 2000 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.372268

    Articles: DFG German National Licenses
  10. 10
    Yoshikawa, M. ; Kunzer, M. ; Wagner, J. ; Obloh, H. ; Schlotter, P. ; Schmidt, R. ; Herres, N. ; Kaufmann, U.

    [S.l.] : American Institute of Physics (AIP)
    Published 1999
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We have studied band-gap renormalization and band filling in Si-doped GaN films with free-electron concentrations up to 1.7×1019 cm−3, using temperature-dependent photoluminescence (PL) spectroscopy. The low-temperature (2 K) PL spectra showed a line-shape characteristic for momentum nonconserving band-to-band recombination. The energy downshift of the low-energy edge of the PL line with increasing electron concentration n, which is attributed to band-gap renormalization (BGR) effects, could be fitted by a n1/3 power law with a BGR coefficient of −4.7×10−8 eV cm. The peak energy of the room-temperature band-to-band photoluminescence spectrum was found to decrease as the carrier concentration increases up to about 7×1018 cm−3, followed by a high-energy shift upon further increasing carrier concentration, due to the interplay between the BGR effects and band filling. The room-temperature PL linewidth showed a monotonic increase with carrier concentration, which could be described by a n2/3 power-law dependence. © 1999 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.371377

    Articles: DFG German National Licenses
  11. 11
    Yoshikawa, M. ; Saitoh, K. ; Ohshima, T. ; Itoh, H. ; Nashiyama, I. ; Yoshida, S. ; Okumura, H. ; Takahashi, Y. ; Ohnishi, K.

    [S.l.] : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Oxide layers etched at an angle were fabricated on a 6H-SiC substrate by varying etching time in diluted hydrofluoric acid, and 6H-SiC metal–oxide–semiconductor structures with various oxide thicknesses were formed. High-frequency capacitance–voltage measurements were carried out for determining the change in gate voltages corresponding to the midgap condition as a function of the thickness of the oxide layer, and the depth profile of trapped charge density in the oxide was estimated from the result. It is found that negative charges build up near the 6H-SiC/SiO2 interface, and that positive charges accumulate in the region at 40 nm from the interface. No significant difference is observed in the depth profiles of the trapped charge density between the oxide layers on the carbon and silicon faces. The origin of these trapped charges is discussed in conjunction with the carbon-related compounds in the oxide layers. © 1996 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.362817

    Articles: DFG German National Licenses
  12. 12
    Yoshikawa, M. ; Maegawa, M. ; Katagiri, G. ; Ishida, H.

    [S.l.] : American Institute of Physics (AIP)
    Published 1995
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Polarized Raman spectra around trenches formed on (100) silicon wafers have been measured and it has been found that the peak frequency shift varies with the polarization configuration, suggesting that anisotropic stresses occur around the trenches. The different stress components have been calculated by the use of the polarization Raman technique and it was found that the stress distribution of each component approximately agrees with that of each component simulated by a finite element method. Polarized Raman spectroscopy is a powerful technique for the estimation of an anisotropic stress of an electronic silicon device in situ. © 1995 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.360287

    Articles: DFG German National Licenses
  13. 13
    Yoshikawa, M. ; Ishida, H. ; Ishitani, A. ; Murakami, T. ; Koizumi, S. ; Inuzuka, T.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1990
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We have measured Raman spectra of a diamond film prepared on the (111) surface of cubic boron nitride(c-BN) by the dc plasma chemical vapor deposition method. The polarization property of the Raman line of diamond agrees well with that of LO phonon for the (111) surface of c-BN. The agreement between the polarization property of Raman lines of diamond and c-BN indicates a possibility of the heteroepitaxial growth of the diamond film on the (111) surface of c-BN. It is found that the diamond layers on c-BN are under tensile stress of 2.2×1011 dyn/cm2. The value of the corresponding tensile strain agrees well with the lattice mismatch calculated from the lattice constants of c-BN and diamond, supporting the possibility of the heteroepitaxial growth of the diamond film. Raman spectroscopy is a powerful technique not only to estimate the stress in the diamond film but also to determine the crystallographic orientation.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.103656

    Articles: DFG German National Licenses
  14. 14
    Yoshikawa, M. ; Ishida, H. ; Ishitani, A. ; Koizumi, S. ; Inuzuka, T.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1991
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We have measured Raman spectra of a diamond film prepared on the (100) surface of cubic boron nitride(c-BN) by the dc plasma chemical vapor deposition method. It is found that the polarization property of the Raman line of diamond coincides well with that of the LO phonon for the (100) surface of c-BN. The coincidence between the polarization property of Raman lines of diamond and c-BN evidences heteroepitaxial growth of the diamond film on the (100) surface of c-BN.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.104316

    Articles: DFG German National Licenses
  15. 15
    Yoshikawa, M. ; Katagiri, G. ; Ishida, H. ; Ishitani, A. ; Akamatsu, T.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1988
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Raman spectra of diamondlike amorphous carbon (a-C) films prepared by the sputtering method have been measured as a function of the excitation wavelength. The Raman spectral profiles vary sensitively, reflecting the change of absorption spectra associated with π-π* electronic transitions with the hydrogen content of the films. From a comparison between Raman and electronic absorption spectra, it is confirmed that the Raman spectral variation with the excitation wavelength is due to the π-π* resonant Raman scattering from π-bonded (sp2) carbon clusters.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.99060

    Articles: DFG German National Licenses
  16. 16
    Yoshikawa, M. ; Katagiri, G. ; Ishida, H. ; Ishitani, A. ; Ono, M. ; Matsumura, K.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1989
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We have measured Raman spectra of diamond films prepared by a hot-filament method and found that diamond layers on Si substrates are under compressive strain. The degree of the strain is found to increase with increasing nondiamond component in the diamond films. It is shown that Raman spectroscopy is a powerful method to estimate the crystalline quality, especially the strain in the diamond films.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.101951

    Articles: DFG German National Licenses
  17. 17
    Yoshikawa, M. ; Iwagami, K. ; Ishida, H.

    [S.l.] : American Institute of Physics (AIP)
    Published 1998
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We have measured the cathodoluminescence spectra around the gate electrode in the cross section of a GaAs metal-semiconductor field-effect transistor with a detector and proposed a new technique to estimate the carrier concentration and stress in electronic devices, using cathodoluminescence spectroscopy. From a comparison between maps of the peak intensity and peak-energy shift, it is found that there is heavy carrier doping in the drain and source regions and that the carrier concentration is about 6×1017 atoms/cm3. The carrier concentration estimated from the peak-energy shift agrees well with that obtained from the capacitance–voltage method. Furthermore, it is found that there is hardly any carrier doping and that stresses are relaxed at a distance of about 2 μm from the gate electrode. Cathodoluminescence spectroscopy is a useful technique for estimating the two-dimensional distribution of the carrier concentration and stress in electronic devices within a short amount of time. © 1998 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.368238

    Articles: DFG German National Licenses
  18. 18
    Yoshikawa, M. ; Katagiri, G. ; Ishida, H. ; Ishitani, A. ; Akamatsu, T.

    [S.l.] : American Institute of Physics (AIP)
    Published 1988
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Raman spectra of diamondlike amorphous carbon (a-C) films prepared under atmosphere with various hydrogen gas content have been measured as a function of excitation wavelength. The Raman spectral profiles vary with excitation wavelength depending on electronic absorption spectra associated with π-π* electronic transitions. Dependence of Raman spectra on excitation wavelength is interpreted in terms of π-π* resonant Raman scattering from aromatic rings with various sizes rather than polyene chains. The relative intensity of a 1400 cm−1 band against a 1530 cm−1 band is found to decrease with an increase of sp3 content in a-C films. It is shown that the relative intensity can be used as a parameter for sp3 content.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.342063

    Articles: DFG German National Licenses
  19. 19
    Nagai, I. ; Takahagi, T. ; Ishitani, A. ; Kuroda, H. ; Yoshikawa, M.

    [S.l.] : American Institute of Physics (AIP)
    Published 1988
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Epitaxial growth of a silicon thin film has been accomplished at a temperature lower than 650 °C by electron cyclotron resonance plasma chemical vapor deposition using an ultrahigh vacuum chamber. Ar plasma from the same electron cyclotron plasma ion source is also used for surface cleaning of the substrate. The relationship between the cleaning condition of a substrate and the quality of an epitaxially grown silicon film is examined in detail. The energy of Ar plasma in the cleaning process should be kept lower than 100 eV in order to obtain films of good crystal quality. Otherwise, damage by Ar ion bombardment cannot be restored by annealing at lower than 700 °C. The epitaxial growth also should be carried out without the accelerating bias voltage to avoid residual compressive stress in the film. An epitaxial film with perfect crystal structure (indicating only a Kikuchi pattern of reflection of high-energy electron diffraction) is obtained at the substrate temperature of 710 °C.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.342429

    Articles: DFG German National Licenses
  20. 20
    Ikeda, K. ; Nagayama, Y. ; Itoh, T. ; Kawamori, E. ; Okamoto, Y. ; Tamano, T. ; Yamaguchi, N. ; Yatsu, K. ; Yoshikawa, M.

    [S.l.] : American Institute of Physics (AIP)
    Published 1999
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    Behavior of impurity ions has been investigated using visible spectroscopy in the GAMMA10 tandem mirror. A 40 channel visible spectrometer system has been developed for measurements of the ion temperature and ion flow velocity. The spectrometer consists of a 100 cm monochromator, a 40 channel optical fiber array and an image intensifier tube coupled with a charge coupled device TV camera. The spectra from low ionization states of oxygen and carbon are measured in ion cyclotron range of frequency heated plasmas. High ion temperatures (3–10 keV) of O4+ are observed in the anchor region, where the minimum B mirror field is produced by baseball coils. The O4+ ion is heated by the fourth harmonic frequency of O4+, which is most likely due to the cyclotron higher harmonic damping. © 1999 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1149346

    Articles: DFG German National Licenses