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Volume 48, Issue 3
Displaying 1-48 of 48 articles from this issue
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45th Vacuum Symposium Proceedings (Osaka 2004)
Review
Letters
  • Study of Damage of Storage Ring Vacuum Chamber by 8 GeV Electron Beam Abort at SPring-8
    Tetsuhiko YORITA, Masaya OHISHI, Noritaka KUMAGAI, Haruo OHKUMA, Hirot ...
    2005 Volume 48 Issue 3 Pages 103-105
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.103
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    The 8 GeV electron beam stored on the SPring-8 storage ring finally hits the vacuum chamber wall, especially stainless steel chamber wall of 0.7 mm thickness in the injection section, when the operation is suddenly stopped by interlock system for safety. At that time the localized heat load is generated in the stainless steel material as a result of the dense electro-magnetic shower. Because of the several times such heat loads, the stainless steel chamber has been broken and vacuum also has. On the cross section of the broken stainless steel wall, one can see the evidence of the degeneration or melting down of the stainless steel which is well described by the cascade calculation for the high energy electro-magnetic events using GEANT31). To avoid such a vacuum break, a thicker stainless steel chamber has been installed and an Al damper, in which density of electro-magnetic shower is low because of its small atomic number, has been developed.
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  • Application of MO-type Vacuum Flange to Accelerator Beam Duct
    Yusuke SUETSUGU, Mitsuru SHIRAI, Michio OHTSUKA
    2005 Volume 48 Issue 3 Pages 106-108
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.106
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    The MO-type vacuum flange, which can provide a gapless connection between flanges, was studied experimentally aiming to apply it to the beam duct of high-current accelerators. A test flange showed a good vacuum sealing property although the flange had a complex aperture, that is, a combination of a circle and a rectangle. The vacuum sealing was successfully achieved with a reasonable fastening force, and was kept even after a baking at 250°C for 24 hours. The structural analysis well reproduced the observed deformation of flange, and utilized to optimize the flange structure. The MO-type vacuum flange was found to be a promising one for the connection flanges of the beam duct with a complicated aperture in the future accelerators.
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  • Application of Boron Nitride Thin Films to Cutting Tools (2)
    Masao NOMA, Tetsutaka KASHIHARA, Eiji KOMATSU
    2005 Volume 48 Issue 3 Pages 109-111
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.109
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    This study described the influence of BN coating conditions on cutting performance. In SKD61 cutting test, cutting performance of end-mill coated by BN thin film depended on bombardment conditions and BN coating conditions. This BN coating end-mill was two times long as TiAlN coating end-mill.
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  • Gas Desorption of Inner Coating Materials Used for Cathode Ray Tube after Electron Beam Irradiation
    Masao HASHIDA, Yuko HIROHATA, Tomoaki HINO, Hidekazu YAMADA, Akio KOID ...
    2005 Volume 48 Issue 3 Pages 112-114
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.112
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    For inner coating material of cathode ray tube (CRT), the effect of an electron beam irradiation on the gas desorption was examined by using thermal desorption spectroscopy. The major species desorbed from the electron-irradiated sample were CO2 and H2O in the temperature range below 1000 K. Compared with the spectra of un-irradiated sample, the desorption rates of H2O and CO2 in the irradiated sample largely decreased in the lower temperature region. The residual gases amounts of H2O and CO2 decreased with increase of electron energy. For example, the residual gas amounts in the sample irradiated by electron beam with energy of 2 keV were a factor of three smaller than those un-irradiated sample. The surface morphology of the irradiated sample showed more porous structure, compared with that of the un-irradiated sample.
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  • Seppen-Katamuki Chart Based on the Mesurement of the Local Emission Currents
    Kazuhito NISHIDA, Fumio IWATSU, Hiroshi MORIKAWA
    2005 Volume 48 Issue 3 Pages 115-117
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.115
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    The distribution of S-K plots due to the change of work function, the radius and emission area of field emitter have been studied based on the measurement of the local emission currents. Even when the surface of the emitter is kept at the same condition, S-K plots are lined up on a straight line with a slope of an applied voltage. This tendency is attributed to the fluctuation of the measured currents due to the fluctuation of the applied voltage or an emission current itself. A parameter of various surfaces is compared by the K values of straight lines for the same S values in such case other parameters are constant. Therefore S-K chart is thought to have additional information comparing with an simple Fowler-Nordheim plot (log (I/V2)-1/V plot), with which work function changes are estimated by a slope of plot only.
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  • Study on Secondary Electron Emission from Carbon Materials
    Michiru NISHIWAKI, Shigeki KATO
    2005 Volume 48 Issue 3 Pages 118-120
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.118
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    A new aspect of problems caused by secondary electron emission from a solid surface irradiated by energetic particles has recently emerged in some fields of science and industry. In a particle accelerator, for example, a problem of electron cloud instability has emerged. In this report, we focused on secondary electron emission from carbon materials to be compared with already reported some metals and TiNx materials. DLC (Diamond Like Carbon), diamond (110), amorphous carbon, HOPG (Highly Oriented Pyrolytic Graphite) and isotropic graphite were prepared to carry out a series of measurements of secondary electron yields (SEYs) and in-situ surface characterizations by X-ray photoelectron spectroscopy (XPS). The measurements were done under the surface conditions as follows; as-received, after electron beam irradiation and after sputter cleaning with Ar+ ion beam. The maximum SEYs in its primary electron energy dependence of carbon materials were found to be around 1 after sputter cleaning. These low SEYs for the carbon materials verified our hypothesis that graphitization at the surfaces by electron beam irradiation in UHV was a reason for decreases of SEYs for the metals and TiNx materials.
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  • Structure and Its Evolution of In Island Films on Si Substrates Revealed in Their Depth-profiles of X-ray Photoelectron Spectroscopy
    Shogo SATO, Takeo NAKANO, Shigeru BABA
    2005 Volume 48 Issue 3 Pages 121-123
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.121
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    The island structure of indium has been investigated by employing the depth profile measurement of XPS. Indium films of 30∼180 nm (in mass thickness) were deposited on silicon substrate by vacuum evaporation at 80°C. The island structure was confirmed by AFM as the substrate surface was filled with islands. In an XPS apparatus, films were sputter-etched with Ar ion to obtain the depth profile. On plotting the XPS signals of In and Si against the sputter time normalized by the deposited amount, the depth profiles of films of various thicknesses were found to have a curve in common. We can explain this universal relation by a model in which the islands of the same form completely cover the substrate surface, and shrink as they are sputtered keeping their similarity. The agreement of the experimental result with our model also suggests that the In islands do not change their form during the growth.
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  • Electroluminescence Properties of InGaAsSbN Quantum Well Diodes Grown by Molecular Beam Epitaxy
    Tomokatsu NAKAGAWA, Yuichi KAWAMURA, Naohisa INOUE
    2005 Volume 48 Issue 3 Pages 124-126
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.124
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    InGaAsSbN quantum well diodes on GaAs substrates and InP substrates were grown by molecular beam epitaxy (MBE) and their electroluminescence properties were studied. It was found that a marked carrier localization effect was observed at low temperature for the InGaAsSbN quantum well diodes on GaAs, while not for the diode on InP. This might be related to the high In composition in the latter structure.
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  • Alloying at ZnS/ZnO Heterointerface Grown by Molecular Beam Epitaxy
    Kazuto KOIKE, Gen-you TAKADA, Kenji HAMA, Takuma HAMA, Hi-izu OCHI, Ke ...
    2005 Volume 48 Issue 3 Pages 127-129
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.127
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    Molecular beam epitaxial growth of a wurtzite ZnS/ZnO heterostructure on a-plane sapphire substrate is reported. X-ray diffraction and cathodoluminescence measurements revealed the formation of a ZnOS alloy layer at the heterointerface. Bandgap bowing parameter for the ZnO-ZnS binary system was roughly estimated to be ∼4.1 eV using an intense visible emission from the interface layer. Such a large bowing is due to the difference in electronegativity between S and O atoms. It is also found that the visible emission peak was pronounced by an ex-situ thermal annealing due to the progress of alloying.
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  • Characterization of Solid Oxide Fuel Cell Having a Thin YSZ Electrolyte Film Grown by RF Magnetron Sputtering in Mixtures of Argon and Oxygen
    Akifumi NISHIMOTO, Tomoaki MIICHI, Akiyoshi NAGATA
    2005 Volume 48 Issue 3 Pages 130-132
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.130
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    The performance of a single solid oxide fuel cell (SOFC) was studied using a thin yttria-stabilized zirconia (YSZ) electrolyte film grown by RF magnetron sputtering in mixtures of argon and oxygen. It is found that crystal system of YSZ electrolyte film controlled by plasma sputtering added oxygen to argon. The density of YSZ electrolyte film was improved with an increase of (111) cubic system by adding 14% oxygen. Maximum current density of a single SOFC having YSZ electrolyte film prepared by adding 14% oxygen obtained 147.5 mA at terminal voltage of 239 mV at the operating temperature of 1000°C. Moreover the resistance of the cell reduced from 9.1 Ω to 4.9 Ω.
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  • Transfer Method of Pb(Zr, Ti)O3 Epitaxial Thin Flms onto Glass Substrates and Evaluation of Their Dielectric Properies
    Kenichiro TERADA, Takaaki SUZUKI, Isaku KANNO, Hidetoshi KOTERA, Kiyot ...
    2005 Volume 48 Issue 3 Pages 133-135
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.133
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    We have successfully transferred epitaxial single crystal PZT (Pb(Zr, Ti)O3) thin films from MgO substrates onto glass substrates by using micro fabrication process. The internal compressive stress of about 200 MPa in the epitaxial PZT thin films was released after the transference. The relative dielectric constant of the PZT thin films increased from 239.4 to 332.9 after the transference with a small decrease of polarization. The crystallinity and crystal orientation of the PZT thin films on the glass substrates were the same to those of epitaxial virgin PZT thin films on the MgO substrates. The transfer process is useful for a fabrication of PZT thin film MEMS devices on any substrates.
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  • Performance of Convectron Gauge Operated by a Power Supply Cable of 500 m Long
    Yoshihiro SATOH, Tomio KUBO, Hiromi HISAMATU, Yoshio SAITO, Norio NAKA ...
    2005 Volume 48 Issue 3 Pages 136-138
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.136
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    A Pirani gauge is usually operated in an accelerator for monitoring the pressure in the beginning of the pump down process. In the high-intensity proton beam accelerator, the gauge controller/power supply, including some semiconductor electronic devices, is often failed due to high levels of radiation, when being installed near the accelerator. In order to install the power supply far out of the tunnel, performance of the Convectron gauge was examined by using longer cables than catalog-specified cable. The gauge was tested with cables of 3 to 500 m long. An inaccurate value in the pressure reading was indicated at the pressure above 1000 Pa, when the cable length was 200 m long, or more. The voltage offset generated by cable resistance exceeds an acceptable input range of the amplifier. Remodeling the controller, a long cable of 500 m long was able to be adopted.
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  • Influence of Temperature and Humidity on Partial Pressure Measurement using Dual Pressure Gauges
    Atsushi SUZUKI, Akira KUROKAWA, Hidehiko NONAKA, Shingo ICHIMURA
    2005 Volume 48 Issue 3 Pages 139-141
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.139
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    Taking into account the utilization of partial pressure measurement under various temperatures and humidity, their influence on this measurement with a capacitance manometer and a quartz friction pressure gauge (Q-gauge) is studied. With increasing humidity, a Q-gauge pressure reading, calibrated by air gas, decreases as well as when the hydrogen leakage is detected. To avoid this error by humidity for the hydrogen sensing, we tried to compensate influence of humidity using a humidity coefficient which is calculated from the humidity dependence of the Q-gauge pressure reading at constant temperature, and suppressed to one-fifth of the fluctuation of the Q-gauge pressure reading background due to humidity change. Regarding to influence of temperature on the Q-gauge pressure reading, it is calibrated by the temperature dependence at low humidity. Finally, influences of temperature and humidity on the hydrogen sensing can be reduced by the calculation below the reading by 0.6 at.% of hydrogen gas.
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  • Seal Reliability of the Combination of ConFlat Type Bakable Knife-edge Flanges in Nominal Diameter of 305 mm Conforming to JVIS 003 and a Gasket of Compatible with ISO 3669
    Satoshi KUROKOUCHI, Toshio KIKUCHI, Hitoshi AKIMICHI, Masahiro HIRATA
    2005 Volume 48 Issue 3 Pages 142-144
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.142
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    While a lot of commercially available knife-edge bakable flanges interchangeable with ConFlat type sealing system have been widely circulated and applied in UHV apparatus, their compatibility is occasionally missed in mating flanges with a nominal outer diameter of 305 mm owing to the difference of detailed dimensions between JVIS 003 and ISO 3669 standards; the dimension of gasket end in JVIS 003 is 0.3 mm larger than that of ISO 3669. In the combination of a flange of ISO 3669 with a gasket of JVIS 003, the outer rim of the gasket is larger than the gasket end on flange. On the contrary, the combination of a flange of ISO with a gasket of ISO 3669 makes a gap of approximately 0.6 mm at its maximum between the gasket end on the flange and outer rim of the gasket. Influence of this mismatching in dimensions on sealing performance was studied experimentally. While combinations required a relatively higher tightening torque, reliability in sealing was not loosed under careful tightening.
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  • Secondary Electron Emission from Alumina with a Multi-pulse Irradiation Method
    Shinichiro MICHIZONO, Yoshio SAITO, SUHARYANTO, Yasushi YAMANO, Shini ...
    2005 Volume 48 Issue 3 Pages 145-147
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.145
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    Surface flashover on the alumina ceramics is one of the most serious problems for developing the dielectric insulation. The flashover takes place by (1) multipactor, electron multiplication on the surface and/or (2) discharge of the accumulated charges (due to multipactor). Since the multipactor sometimes induces localized surface melting, surface charging is evaluated not only at room but also at high temperature. The alumina ceramics with higher purity show lower surface chargings at room temperature and non-chargings at 650°C. A sapphire (single crystal alumina) disk shows high surface charging even at 650°C. Considering the poor performance of the sapphire for the rf window usage, less charging materials at high temperature is indicated to be the promising candidates for the dielectric insulation.
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  • Development of a Compact Photon Absorber for a Multi-pole Wiggler
    Kazuhiro TAMURA, Masaya OISHI, Haruo OHKUMA, Shiro TAKANO, Mitsuhiro M ...
    2005 Volume 48 Issue 3 Pages 148-150
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.148
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    A compact photon absorber for the accelerator diagnosis beamline #2 of the SPring-8 storage ring, which withstands high heat load of the synchrotron radiation from a multi-pole wiggler, has been developed. In order to make the absorber compact, two absorber blocks made of GlidCop with a different tilt angle of surface have been arranged in tandem in the vacuum chamber. The front absorber intercepts upper and lower parts of the synchrotron radiation, and the rear one absorbs central part of the synchrotron radiation. Wirecoils made of copper have been inserted in the water-cooling channels of each absorber block to increase the heat transfer coefficient. The result of thermal and stress analysis with the ABAQUS code shows that the absorber has the fatigue strength of more than 5000 times at the maximum heat load of the synchrotron radiation from the wiggler.
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  • Formation of Diamond-like Carbon Thin Films by Ion Beam Assisted Deposition Method
    Isao NAKAMURA, Ichiro TAKANO, Michiko SASAKI, Masaru TAKASHIKA, Tomohu ...
    2005 Volume 48 Issue 3 Pages 151-153
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.151
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    The mechanical properties of diamond-like carbon (DLC) thin films on SUS304 substrate have been studied. DLC thin films were prepared by the ion beam assisted deposition method. In this method, He+ ion irradiation was carried out in a C2H4 gas atmosphere. He+ ions were accelerated at an energy of 15 keV, and the ion beam current densities were changed from 10 to 100 μA/cm2. Atomic concentration and structure of the films were investigated by X-ray photoelectron spectroscopy and Raman spectroscopy. The mechanical properties of hardness and friction coefficient were determined using the Knoop hardness tester and the pin-on-disk tribometer.
    The DLC thin films had amorphous structure that composed chiefly of graphite and disorder of graphite states. The Knoop hardness of the films increased with increasing He+ ion current density, and the film prepared at a current density of 80 μA/cm2 showed the maximum Knoop hardness value of 890 kgf/cm2. The friction coefficient of the film prepared at a current density of 60 μA/cm2 indicated lower value than that of the other current densities. From these results, it was cleared that the mechanical properties and structure of DLC thin films were greatly affected by the He+ ion beam current density.
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  • Electrical Properties of High-quality CVD Diamond p-i-p Structures at High Electric Fields
    Michinori YAMAMOTO, Mitsuhiro HAMADA, Tokuyuki TERAJI, Toshimichi ITO
    2005 Volume 48 Issue 3 Pages 154-156
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.154
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    In this study, we have fabricated high-electric-field-applicable p-i-p structures using a photolithographic process with high-quality homoepitaxial diamond grown by means of high-power microwave-plasma chemical-vapor-deposition (CVD) method. Current-voltage (I-V) characteristics of the diamond p-i-p devices revealed rapid increases in current due to impact excitation events of electrons from the valence band whereas such space-charge-limited currents as I ∝ V 2 were observed at sufficiently high electric fields. Substantial differences in the I-V characteristics observed among the p-i-p devices strongly depended on the electronic properties of the CVD diamond i layers employed. Electroluminescence measured for a p-i-p device was compared with cathodoluminescence taken from the diamond i layer.
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  • Growth and Characterization of P-doped CVD Diamond (111) Thin Films Homoepitaxially Grown using Trimethylphosphine
    Hideki WADA, Tokuyuki TERAJI, Toshimichi ITO
    2005 Volume 48 Issue 3 Pages 157-159
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.157
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    We have homoepitaxially grown phosphorus-doped chemical-vapor-deposited (CVD) diamond (111) films using trimethylphosphine (TMP) as a more convenient dopant gas and have measured their electrical properties. On one hand, sheet Hall coefficients, RH, obtained at various temperatures, T, above room temperature (RT) by AC Hall method were all negative and had the maximum in the |RH|-1/T plots, suggesting that two types of electrons with substantially different mobilities existed in the P-doped specimens. On the other hand, a hopping conduction with an activation energy of 0.013 eV was observed below RT. A two-carrier model was proposed to consistently explain all of these data obtained. From a curve fitting procedure, we deduced the RT electron mobility of 100 cm2/Vs in the conduction band, the activation energy of 0.59 eV from the donor to the conduction band and the compensation ratio of 1.6%. The smaller carrier mobility was estimated to be ≈ 1 cm2/Vs. It is also found that TMP yields a much higher doping efficiency for n-type diamond synthesis than PH3 does.
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  • Characterization of the Oxidized CVD Diamond (100) Surfaces using STM, PEEM and XPS
    Jun NAKAMURA, Toshimichi ITO
    2005 Volume 48 Issue 3 Pages 160-162
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.160
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    We have investigated atomic structures of B-doped microwave-plasma chemical-vapor-deposited (CVD) diamond (100) surfaces using an ultra-high-vacuum scanning tunneling microscope (STM), photoelectron emission microscopy (PEEM) and X-ray photoelectron spectroscopy (XPS). STM images taken from the diamond surfaces at the various oxidization stages reflected corresponding surface structures, from which the oxygen sites and oxidization process of the as-grown CVD diamond were discussed. PEEM images demonstrated a rather high electron emissivity of the as-grown CVD diamond surface and decreasing emissivities after light oxidization. XPS spectra taken from these surfaces demonstrated corresponding changes in shape with oxidization.
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  • Analysis of the Electronic States and Ferromagnetism in Diluted Magnetic Semiconductors Within the Dynamical Cluster Approximation
    Daisuke MATSUNAKA, Hideaki KASAI, Wilson Agerico DIÑO, Hiroshi ...
    2005 Volume 48 Issue 3 Pages 163-165
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.163
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    We present an analysis of the electronic states in diluted magnetic semiconductors, applying the dynamical cluster approximation. We show that the polarization of the carrier spins is suppressed by the antiferromagnetic superexchange interaction between nearest-neighbor sites more strongly at the higher impurity concentration.
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  • Preparation and Characterization of Ferromagnet/Superconductor Structures
    Yuki EBARA, Kazuyuki HIDAKA, Satoru KISHIDA
    2005 Volume 48 Issue 3 Pages 166-168
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.166
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    We deposited the ferromagnetic films, Ni or Fe, on the YBa2Cu3Oy (YBCO) thin films by rf magnetron sputtering technique, and investigated the effects of ferromagnetic films on superconducting characteristics in Ni or Fe/YBCO specimens. From the results, we found that the superconducting transition temperature decreased with increasing the thickness of the magnetic films, in other words superconducting characteristics were degraded by depositing the magnetic films on the high-Tc cuprate superconductors. This indicates that it is possible to fabricate weak electric coupling for Josephson junctions based on the cuprate superconductors by depositing the magnetic films on them.
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  • The Improved Characteristics Through Laser Annealing for the Al-Doped ZnO Films Prepared by the Laser Ablation Method
    Shigeyasu HOKI, Akio SUZUKI, Takanori AOKI, Tatsuhiko MATSUSHITA, Masa ...
    2005 Volume 48 Issue 3 Pages 169-171
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.169
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    ZnO films doped with 1.5 wt% Al2O3 (AZO films) have been deposited, in oxygen with a partial pressure of 0.1 Pa, on glass substrate using a pulsed laser deposition technique with an ArF laser (λ = 193 nm). When as-deposited, a repetition rate of 10 Hz, an energy density of 4 J/cm2, and an irradiation time of 30 min were used. After an annealing performed with the energy density 10∼40 mJ/cm2 for 30 min, it was found that resistivity decreased from 1.26×10-3 Ω · cm to 9.58×10-4 Ω · cm and surface roughness of the films Ra decreased from 2.1 nm to 1.8 nm.
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  • Transparent Conducting ZnO Films Prepared by Pulsed Laser Deposition Method with Varied Wavelengths
    Hideaki AGURA, Hirokazu OKINAKA, Akio SUZUKI, Takanori AOKI, Tatsuhiko ...
    2005 Volume 48 Issue 3 Pages 172-174
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.172
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    Approximately 100-nm-thick transparent conducting AZO (ZnO doped with 1.5 wt.% Al2O3) films have been deposited on glass substrates using a pulsed laser deposition method with an ArF excimer laser (λ = 193 nm) and a Nd:YAG laser (λ = 266, 355, 532 nm). In all experiments, a repetition rate of 10 Hz, an energy density of 2 J/cm2, and an irradiation time of 10-60 min (6000-36000 shots) were used. XRD and FE-TEM observations revealed the fact that there is a remarkable difference of the crystal structures in the films fabricated with various wavelengths of the lasers: at 532 nm, it was found that the whole structure was melted.
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  • Impact Ionization Phenomenon of TiO2 Rutile (110) under High Electric Field and Its Application
    Hiroshi HASHIMOTO, Tokuyuki TERAJI, Toshimichi ITO
    2005 Volume 48 Issue 3 Pages 175-177
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.175
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    We applied high electric fields to titanium oxide (TiO2) as a material suitable for photocatalysis in order to electrically generate high-energy holes and electrons using impact ionization processes. In current-voltage (I-V) measurements, currents rose suddenly at a threshold voltage, indicating that an impact ionization phenomenon occurred in TiO2. The threshold voltage was controllable from 10 to 170 V by varying the metal electrode thickness. This means that an electric field enhancement effect was significant at the edge of the thin film electrode. At higher voltages, there was observed a relation I ∝ V 2, indicating that space-charge-limited currents dominated the currents flowing in the specimen and prevented the specimen from possible rapid field breakdown.
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  • Optical Recording Characteristics of WO3 Films Prepared by Pulsed Laser Deposition Method (II)
    Kenji TANABE, Takanori AOKI, Akio SUZUKI, Tatsuhiko MATSUSHITA, Masahi ...
    2005 Volume 48 Issue 3 Pages 178-180
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.178
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    Tungsten oxide films were deposited on glass substrates (Corning #7059) and polycarbonate substrates by a pulsed laser deposition technique using the both targets WO3 and WO2. At this time, the difference in the transmittance, ΔT, between the annealed state and the as-deposited state of the films fabricated with WO2 target was about 70% at the wavelength of 400 nm and that of the films prepared with the WO3 target was about 60%. From XRD spectra and XPS spectra, it was found that the as-deposited state was an oxygen-deficient amorphous state and the crystalline state was caused by absorbing oxygen through the annealing process (at 500°C×10 min).
    It was confirmed from the revolution-test of the disc structure that the values of CNR obtained at the write peak power 7.5∼9 mW was more than 50∼60 dB. From SEM images of top the view, it was presumed that a recording mechanism was related to a cooperative effect of the reflectivity change and the volume change induced in the recorded dot.
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  • Preparation of Bi2Sr2Can-1CunOy Superconducting Thin Films by RF Magnetron Sputtering Under External Magnetic Field
    Takahiro ONISHI, Kenji SAITOU, Yukari OUCHI, Naoki FUJIWARA, Satoru KI ...
    2005 Volume 48 Issue 3 Pages 181-183
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.181
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    We deposited Bi2Sr2Can-1CunOy (Bi-based) superconducting thin films by the RF magnetron sputtering under external magnetic field of about 1 T. The as-deposited films were Bi-2223 single-phase, and their Tc was about 70 K without any in-situ or ex-situ annealing process. Therefore, this method is thought to be useful for obtaining the Bi-based films with high Tc.
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  • Sputtering Property of Thin Electrolyte Film with Solid Oxide Fuel Cell Grown by Magnetic Field Control of Helicon Wave Excited Plasma
    Shinji FUJIMURA, Akiyoshi NAGATA
    2005 Volume 48 Issue 3 Pages 184-186
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.184
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    Helicon wave excited plasma (HWP) controlled by magnetic mirrors was applied to sputtering growth of a thin yttria-stabilized zirconia (YSZ) electrolyte film with solid oxide fuel cell (SOFC). Electron energy increased as increasing mirror field coil current from 4 to 15 A and its maximum value obtained at mirror field by coil current of 15 A. Furthermore, XRD intensity of (111) cubic system of a sputtered YSZ film also increased by adding magnetic mirrors. As a result, it was found that energy property of HWP and crystal structures of a sputtered YSZ film could be improved largely by reduction of particle energy losses due to the plasma confinement effect of magnetic mirrors.
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  • Characteristics of Substrate Current in Magnetron Sputtering of Nickel with Multipolar Magnetic Plasma Confinement Assisted by Inductively Coupled Plasma
    Kazuaki TAKESAKO, Tsuguhisa MIYAMOTO, Keishi KAWABATA
    2005 Volume 48 Issue 3 Pages 187-189
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.187
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    The discharge characteristics in magnetron sputtering of Ni with multipolar magnetic plasma confinement (MMPC) assisted by inductively coupled plasma (ICP) were investigated. When sputtering with MMPC assisted by ICP, the current flowing into the substrate due to Ar+ ions and sputtered Ni+ ions is increased up to 46 mA, about 2.7 times that of a conventional magnetron sputtering system. The substrate current significantly increases in comparison with a conventional magnetron sputtering system as the target dc bias voltage increases. It is shown that a nickel film with the orientation of (111) plane is formed by using ICP.
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  • Study on Localized Growth of Carbon Nanotubes by an Atmospheric Microdischarge
    Hiroyuki YOSHIKI, Rikizo HATAKEYAMA
    2005 Volume 48 Issue 3 Pages 190-192
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.190
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    Carbon nanotubes (CNTs) were synthesized in the local area of a Ni-plated steel needle (φ0.6 mm) by an atmospheric-pressure RF (14 MHz) microdischarge using pure methane (CH4). Twisted CNTs were gregariously grown in the position of 1.5 mm apart from the tip of the needle at a RF power of 4 W, DC bias of -100 V and a discharge time of 2 min. The density of CNTs increased with increasing DC bias. The effect of H2O vapor (partial pressure: 20-25 kPa) addition to CH4 was examined and well aligned graphite nanowhiskers, whose diameter and length were φ70∼100 nm and 5∼10 μm, respectively, grew without the deposition of the soot.
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  • Low Temperature Synthesis of Aligned Carbon Nanotubes by Direct Current Plasma Chemical Vapor Deposition
    Yosuke WATANABE, Yasuaki HAYASHI, Shigehiro NISHINO
    2005 Volume 48 Issue 3 Pages 193-195
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.193
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    The experiments of carbon nanotube (CNT) synthesis were carried out at low temperature by direct current plasma chemical vapor deposition (DC-PCVD). High DC bias voltage was applied to substrates with hot filaments, which were used for preheating and stabilizing plasma before the synthesis. As a result well-aligned CNTs about 60 nm in diameter were successfully obtained in the density of about 109 cm-2 on the surface of the Co film deposited on Si substrate at 500°C.
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  • Magnetic Properties of Fe Nanowire in the Carbon Nanotubes on Ni(111)
    Masanori KISAKU, Tomoya KISHI, Daisuke MATSUNAKA, Wilson Agerico DI&Nt ...
    2005 Volume 48 Issue 3 Pages 196-198
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.196
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    We have investigated the magnetic properties of Fe-filled carbon nanotubes (CNT) on Ni(111), based on the density functional theory. Fe-filled carbon nanotubes (CNT) on Ni(111) exhibit spin-polarization when the Fe wire adheres contrary to the Ni surface side. Fe wire has no spin-polarization when the Fe wire adheres adjacent to the Ni surface side. The bonding states between Ni and C atoms affect the magnetic properties of Fe wire.
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  • Stable Structures and Magnetic Properties of the Fe Adatom on Si(001)
    Kenji SUZUKI, Tomoya KISHI, Daisuke MATSUNAKA, Wilson Agerico DI&Ntild ...
    2005 Volume 48 Issue 3 Pages 199-201
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.199
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    We determine the stable structures of Fe adatoms on Si(001) and investigate their magnetic properties, based on the density functional theory. For the Si(001) surface, we consider the clean surface and the H-terminated surface. We find that the structure of the clean Si surface is reconstructed, but the structure of the H-terminated surface is hardly reconstructed and that the magnetic moment of the Fe adatom on the H-terminated surface is larger than that of the Fe adatom on the clean surface.
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  • The Changes in Surface Morphology of the Heavily Phosphorus Doped Silicon by the Treatment in an Ultrapure Water
    Yuichi SANO, Kazuhisa NAKATSUKA, Masashi KAKIMOTO, Yoshitomo KAMIURA, ...
    2005 Volume 48 Issue 3 Pages 202-204
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.202
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    The morphologies of Si(100) (SI) and heavily P-doped Si(100) (CI) were changed enormously by dipping in ultrapure water at 60°C or 100°C, which was revealed by atomic force microscope (AFM). The dipping at 100°C changed the flat surface of SI into very rough one with grains all over the surface. The surface of CI dipped in 60°C water became rough one similar to the SI surface dipped in 100°C water. On the other hand, after dipping CI in 100°C water, the CI surface was still smooth. This result implies that uniform etching was occurred in this case. In consequence, both oxidation and etching should occur competitively when silicon surface was dipped into the hot water. The X-ray photoelectron spectroscopy (XPS) results showed that the rough surfaces with grains exhibited the SiO2 component. Thus, the SiO2-unclei grown to extended size would prevent the surface from etching, which made the smooth surface rough.
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  • Density Functional Calculations for H2 Adsorption on Fe(OH)3 by Considering Molecular Orientation
    Rifki MUHIDA, Agus SUSANTO, Tomoya KISHI, Tanglaw ROMAN, Wilson A. DI& ...
    2005 Volume 48 Issue 3 Pages 205-207
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.205
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    H2 adsorption on Fe(OH)3 is investigated by using the density functional theory (DFT) for the H2 molecular orientation θ = 10° with respect to the surface normal and that for the H2 molecular orientation θ = 70°. From the PES results of H2-Fe(OH)3 system, we find that for the H2 molecular orientation θ = 10°, a potential well is at Z = 4.2 Å with a depth of around 4.4 meV while for the H2 molecular orientation θ = 70°, a potential well is at Z = 3.0 Å with a depth of around 17.7 meV. The small binding energy and the positions of potential well with respect to the surface of these adsorption states are typical for physisorption.
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  • Ab Initio Study of Cyclohexane Dehydrogenation on Pt(111)
    Muneyuki TSUDA, Wilson Agerico DIÑO, Hiroshi NAKANISHI, Susumu ...
    2005 Volume 48 Issue 3 Pages 208-210
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.208
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    We investigate cyclohexane dehydrogenation on Pt(111) by performing total energy calculations based on the density functional theory (DFT). After interacting with the Pt, the Pt draws an H atom from the cyclohexane, and an H-Pt bond is formed. With the C-H bond broken, cyclohexyl intermediate (C6H11) desorbs from Pt(111). The cleaved H atom, then, moves to the hollow site of Pt(111), and the desorbing cyclohexyl comes back to and adsorbs on Pt(111). The C-H bond cleavage requires an activation barrier of 1.18 eV, which is a little lower than that with a small Pt cluster.
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  • Development of a Time-of-flight Mass Spectrometer Equipped with a Superconducting-tunnel-junction Ion Detector
    Naoaki SAITO, Masataka OHKUBO, Masahiro UKIBE, Akihiro KUSHINO, Akira ...
    2005 Volume 48 Issue 3 Pages 211-213
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.211
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    We have started the development of a new time-of-flight mass spectrometer equipped with Nb/Al superconducting-tunnel-junction detectors. Metal cluster ions were employed to investigate the properties of the superconducting ion detectors. In addition to mass spectroscopy with wide mass range, we have performed impact energy measurement, which enables charge-state discrimination.
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  • Irradiation Effect of keV Region Electron Beam on Bleaching and Cracking of Various Types of Sapphires
    Bo-Hyun LEE, Tokuyuki TERAJI, Toshimichi ITO
    2005 Volume 48 Issue 3 Pages 214-216
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.214
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    Various types of single-crystalline α-Al2O3 have been investigated on bleaching and cracking effects of keV electron beams using scanning electron microscope (SEM) and cathodoluminescence (CL) measurements. These electron-irradiation-induced effects observed at room temperature were different among four types of sapphires examined, namely, Be-diffusion-treated natural, untreated natural, synthetic orange, and synthetic red sapphires. The bleaching phenomenon occurred at electron dosages and the surface cracking phenomenon was subsequently observed at substantially higher dosages. The former was reversible so that an appropriate annealing in an oxygen atmosphere completely removed the bleached areas whereas the latter was a permanent change in structure that was not able to be recovered at all by such a treatment. It is found from these evidences that the crystalline quality of each specimen was well correlated with its beam-dose dependences of the electron-beam-induced phenomena observed. It should be noted that such electron-induced effects were almost completely reduced by the presence of a thin conductive layer on the insulating specimen surfaces.
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  • A Study on Sealing Process of Anodized Al Alloy Film
    Takeshi TSUJITA, Hiroshi SATO, Sonoko TSUKAHARA, Yuuichi ISHIKAWA
    2005 Volume 48 Issue 3 Pages 217-219
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.217
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    Since sealing is an important process to improve the corrosion resistance in practical application of anodized aluminum, we prepared anodic oxide films on A5052 alloy in an oxalic acid bath and a sulfuric acid bath, sealed them at various conditions, and analyzed them by scanning electron microscopy, acid-dissolution examination, admittance measurements and infrared spectroscopy.
    The pore radius of the oxalic acid anodized film was about 5 times larger than that of sulfuric acid anodized film, while the corrosion resistance of the former showed about 2 times higher value than the latter with the same sealed state and amount of hydroxide formed by sealing process of the former was 6 times larger than the latter, respectively. Steam sealing formed dense hydroxide and boiling water sealing formed big coral-like hydroxide, whereas the corrosion resistance of the film sealed by the former showed about 1.5 times higher value than that sealed by the latter, respectively. Thus microstructure of anodic oxide films and their surface morphology after sealing process clearly depended on their anodizing solution and the sealing condition and showed obvious relation to electric and corrosive properties.
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  • Effect of Substrate Materials on Fabrication of Si3N4 Coating by Reactive Spraying
    Tatsuya INAMOTO, Motohiro YAMADA, Masahiro FUKUMOTO, Toshiaki YASUI
    2005 Volume 48 Issue 3 Pages 220-222
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.220
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    Silicon nitride (Si3N4), a kind of non-oxide ceramics, has excellent properties for high temperature application and resistance of wears and corrosion, and is expected as a high temperature material. Reactive plasma spraying process, in which metal element reacts with surrounding active species in plasma, is useful for the spraying of non-oxide ceramics. In this research, Si/Si3N4 coating was fabricated by reactive radio frequency (RF) plasma spraying with graphite substrate. Si3N4 content in the coatings increased with N2 gas flow rate. Vickers hardness of the coatings increased with Si3N4 content in Si/Si3N4 coatings. The maximum content of Si3N4 was 53 wt% its hardness was 1272 Hv.
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  • Fabrication of Aluminum Nitride Coating onto Carbon Steel Substrate by Reactive Plasma Spraying
    Hajime NAKAMURA, Motohiro YAMADA, Masahiro FUKUMOTO, Toshiaki YASUI, K ...
    2005 Volume 48 Issue 3 Pages 223-225
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.223
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    Aluminum nitride (AlN) is one of the attractive ceramics in respect of its excellent properties. It was possible to fabricate Al/AlN composite coatings onto carbon steel substrate by reactive plasma spray process. However, most of the coatings, which include more nitride phase, peeled off due to the difference of thermal expansion coefficient between AlN and carbon steel. It might be possible to prevent peeling off AlN coatings with fabricating functionally graded AlN coating or formation of Al layer between substrate and AlN coating. To fabricate these coatings, it was necessary to control the nitriding reaction. Thus, nitriding process of aluminum powder in the reactive plasma spray process was investigated. Then the coatings were fabricated with changing nitrogen flow rate in the plasma gas. Although it was difficult to fabricate functionally graded AlN coating, it was possible to prevent the peeling off the coatings with formation of Al layer between carbon steel substrate and AlN layer on the surface of the coatings.
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  • Low Energy Electron Diffraction (LEED) Pattern Observation and Intensity-Energy Curve (I-V curve) Evaluation of Fe/Si(111) Surfaces
    Kenji KONDO, Syuji SAKAGUCHI, Takashi MATSUO, Nozomu KAWAI, Shozo HONG ...
    2005 Volume 48 Issue 3 Pages 226-228
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.226
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    We observed the LEED patterns of Fe silicide produced by solid phase epitaxy (SPE) on Si(111) surface. Besides 1×1 and 2×2 LEED pattern observed before, c(8×4) pattern with 575°C annealing after Fe1.5ML deposition at room temperature, 2×2+√3×√3 pattern with 550°C annealing after 5ML deposition and c(4×2) pattern with 550°C annealing after 10 ML deposition were newly observed. Then we acquired I-V curves (Intensity-Energy curve) of typical LEED pattern. To evaluate the reliability of the I-V curve, we compared them each other to be sure the symmetry on the three-fold symmetrical surface and to evaluate the structure change with elevating the annealing temperature. The similarity was evaluated by Pendry's R-factor value. From the experimental result, the I-V curves that can be endured to the structure analysis were obtained.
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  • Observation of the MgO(100) Surface Cleaved in the Different Atmospheres using Electron Stimulated Desorption
    Masahiro ODAKA, Kenji SUZUKI, Takashi TADANAWA, Shoji TAKAGI, Tetsuji ...
    2005 Volume 48 Issue 3 Pages 229-231
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.229
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    The electron stimulated desorption (ESD) ions from the MgO(100) surface cleaved in the methanol were observed by the Quadrupole Mass Spectroscopy (QMS). Also, the angular distributions of the desorbed ions by electron incidence were observed by Time of Flight (TOF) method. In comparison to the results of MgO surfaces cleaved in water and nitrogen atmospheres, it is found that desorbed CH2+, CO+, CH3OH+ ions originate to adsorbed methanol molecules. And OH+ ion, which was observed in MgO cleaved in water, is not observed obviously. All desorbed ions increase as the incidence angle of the electron approaches the direction of step lines on the cleaved surface. Especially CH2+ shows the clearer tendency than the other desorbed ions.
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  • Density Functional Theory Investigation of One-Dimensional Organic-Metallic Multiple-Decked Sandwich Model
    Md. Mahmudur RAHMAN, Rifki MUHIDA, Wilson Agerico DIÑO, Hiroshi ...
    2005 Volume 48 Issue 3 Pages 232-234
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.232
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    We investigate electric and magnetic properties of a benzene-iron complex chain [Fe(C6H6)]∞. By performing first principles calculation based on the spin-polarized density functional theory, we find that this system shows semiconducting behavior having magnetic moment. We also show that this system is stable due to the Fe atom.
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  • Examining Poly(Phenylene Sulfide) Adhesion using Cluster Models
    Tanglaw ROMAN, Melanie DAVID, Wilson Agerico DIÑO, Hiroshi NAKA ...
    2005 Volume 48 Issue 3 Pages 235-237
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.235
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    Density functional theory-based calculations on representative cluster models have been performed to investigate the adhesion strength of poly(phenylene sulfide) (PPS) onto magnesium, silicon and titanium, in addition to previously studied aluminum, copper, silver, and gold. Energy relations of substrate atom interactions with the sulfur end of a PPS monomer showed strongest binding with titanium and aluminum, while the larger transition metals showed the weakest results. A further investigation on the interaction of aluminum with the sulfur atom of a diphenyl sulfide model suggests a strong orientation dependence of the adhesion process, as shown in the greater preference for the in-plane case.
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  • Creation of Novel Structured Nanocarbons Based on Plasma Technology
    Rikizo HATAKEYAMA, Takamichi HIRATA, Wataru OOHARA, Toshiaki KATO, Tak ...
    2005 Volume 48 Issue 3 Pages 238-240
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.238
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    Original approaches using plasma processing technology have been performed in order to develop fullerene- and nanotube-based materials with new functions, where various kinds of plasma sources are devised: pair-ion plasma, alkali-fullerene plasma, and radio-frequency reactive plasma. As a result of the process control of these plasmas we have succeeded in creating novel structured nano carbons such as fullerene dimers, alkali-metal encapsulated fullerenes, individually-aligned pristine single-walled carbon nanotubes, and alkali-metal and/or fullerene encapsulated single-walled carbon nanotubes.
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  • Spectroscopic Measurement of Plasma in the Reactive Plasma Spray Process
    Motohiro YAMADA, Tatsuya INAMOTO, Masahiro FUKUMOTO, Toshiaki YASUI
    2005 Volume 48 Issue 3 Pages 241-243
    Published: 2005
    Released on J-STAGE: August 11, 2006
    DOIhttps://doi.org/10.3131/jvsj.48.241
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    Reactive RF (Radio Frequency) plasma spray process, in which metal element reacts with surrounding active species in plasma, has been receiving great interest to form nitride ceramics thick coatings. It was possible to fabricate TiN, Si3N4 and AlN thick coatings by this process. However, nitriding process has not been elucidated yet. To control the formation degree of the nitride with reactive RF plasma spray process, it is necessary to verify the nitriding process. In this study, plasma temperature and active species in the plasma were investigated by emission spectroscopic measurement. Plasma temperature increased with N2 gas flow rate. Adding H2 in plasma gas increased plasma temperature. Plasma gas fraction of N2 and H2 affected the amount of generating NH radical significantly. However, plasma gas fraction did not affect plasma temperature. Both plasma temperature and the amount of generating NH radical increased with RF power.
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