M. Fujii

Nagasaki University, Nagasaki, Nagasaki, Japan

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Publications (10)14.9 Total impact

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    ABSTRACT: Cosmo-mimetic carbon micro-coils were obtained by the catalytic pyrolysis of acetylene with a small amount of thiophene, and the preparation conditions were examined. The oxidation of a metal catalyst strongly affects the growth of carbon coils. Light emission and a temperature increase of 20-25°C were observed during the reaction, and these have some relationships with the reaction of growing carbon coils. Application of a bias voltage to the substrate was very effective for obtaining a high coil yield. The carbon coils could be graphitized by a heat treatment at 3000°C for 6 hrs in a CO/CO2 atmosphere. TaC micro-solenoids/micro-tubes and other ceramic micro-tubes, such as TiC, TiN, NbC, and NbN, were prepared by the vapor phase metallizing and metallizing/nitriding of the regular and densely coiled carbon coils.
    Journal de Physique IV (Proceedings) 09/1999; DOI:10.1051/jp4:1999856 · 0.35 Impact Factor
  • H. Iwanaga, M. Fujii, S. Takeuchi
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    ABSTRACT: Due to the difference in chemical nature between the opposite polar surfaces, a variety of polarity effects on the morphology and crystallography emerge in zincblende and wurtzite crystals. In this article, a review is given of the effects of polarity on the etched pattern, the twin structure, the growth selectivity and the morphology of particles for IIb–VIb crystals of CdS, CdTe, ZnO, etc.
    Phase Transitions 09/1998; 66(1-4):147-165. DOI:10.1080/01411599808222124 · 1.04 Impact Factor
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    ABSTRACT: Whiskers and ribbon-like single crystals of ß-HfP (hexagonal) have been prepared from HfCl4+PCl3+H2+Ar gas mixtures at 1100–1200 °C using a metal impurity-activated chemical vapour deposition process. The growth conditions, morphology and chemical properties were examined. The 3.5–6.5 mm (average 4 mm) long HfP whiskers were obtained at 1200 °C using Si+Pt or Si+Pd mixed impurities. The HfP whiskers were very stable against oxidation up to 3 h exposure at 1000 °C and for 80 min immersion in concentrated HCl solution at 50 °C.
    Journal of Materials Science 01/1996; 31(21):5709-5715. DOI:10.1007/BF01160819 · 2.37 Impact Factor
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    ABSTRACT: New ternary compound crystals of (Cr0.26Fe0.74)3Si2 have been obtained by an in-situ chemical vapor deposition process, using the in-situ reaction of SUS 410 powder with Si2Cl6 and H2. Well-formed twinned crystals, ball-like crystals and whiskers were simultaneously obtained under the same conditions. The new twinned crystals have the same hexagonal lattice as that of (Cr,Fe)5Si3. The twinned crystals with a diagonal length of 0.3–1 mm and whiskers 3 mm long were obtained at 1100 °C after 2 h. The crystals were much more corrosion and oxidation resistant than was the SUS 410 plate.
    Materials Science and Engineering B 11/1994; 27(2-3):73-79. DOI:10.1016/0921-5107(94)90125-2 · 2.12 Impact Factor
  • S. Takeuchi, H. Iwanaga, M. Fujii
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    ABSTRACT: The characteristic morphology of tetrapod-shaped ZnO particles grown by oxidizing zinc vapour in air has been thoroughly interpreted by a growth process from octahedral multiple-twin embryos. The origin of the tetrapod-shape arises from firstly the formation of octahedral multiple twins due to the small c/a ratio of wurtzite ZnO, secondly the presence of in version-type twin boundaries and thirdly a large growth anisotropy with respect to the crystal polarity.
    Philosophical Magazine A 06/1994; 69(6):1125-1129. DOI:10.1080/01418619408242243
  • H. Iwanaga, M. Fujii, S. Takeuchi
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    ABSTRACT: The prototype morphology of tetrapod zinc oxide particles, which was studied in detail in a previous paper [J. Crystal Growth f128 (1993) 1095] has been interpreted completely by the growth model from a multiple inversion-twin embryo.
    Journal of Crystal Growth 12/1993; 134(3-4-134):275-280. DOI:10.1016/0022-0248(93)90136-K · 1.69 Impact Factor
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    ABSTRACT: The morphology of tetrapod-like zinc oxide particles, produced by oxidizing zinc vapor, has been examined by optical and electron microscopy. In most of the particles, three to four among six angles between four legs of a tetrapod are 102°. The four legs grow along the c-axis from a nucleus which has been identified to have also the wurtzite structure.
    Journal of Crystal Growth 03/1993; 128:1095-1098. DOI:10.1016/S0022-0248(07)80104-7 · 1.69 Impact Factor
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    ABSTRACT: ZnSe crystals were grown by a vapour transport method on a GaAs substrate with a (111) A or (111) B surface. Crystals obtained on the (111) A surface of the substrate were fine crystals and hexagonal plates. Whereas crystals grown on the (111) B were uniform thin films on which trigonal hills and trigonal pyramids developed. These crystallites had a complicated morphology. In addition, the hill and pyramid grown on the (111) B surface contained rotation twins around a polar axis parallel to the growth direction or around the other polar axes.
    Journal of Materials Science 12/1992; 28(15):4068-4072. DOI:10.1007/BF00351234 · 2.37 Impact Factor
  • M. Fujii, H IWANAGA, N SHIBATA
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    ABSTRACT: GaAs needle crystals with the zincblende structure were grown by reacting a mixture of Ga and Ga2O3 with As in a closed quartz tube. The six lateral surfaces of the needles are parallel to the {112} planes. The growth axis is the [111] polar direction. Some of them changed their growth axis from one of the <111 > polar axes to another during growth. Examinations of the crystals by scanning electron microscopy and X-ray diffraction clarified the detailed morphology. The polarity of grown crystals was determined from a study of etch pits revealed on the {111} and {112} planes by an HF+H2O2 etchant.
    Journal of Crystal Growth 01/1990; 99:179-182. DOI:10.1016/0022-0248(90)90508-I · 1.69 Impact Factor
  • M. Fujii, H. Iwanaga, N. Shibata
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    ABSTRACT: GaP whiskers were grown by reacting a mixture of Ga and Ga2O3 with P in a closed quartz tube. The three lateral surfaces of the whiskers are parallel to the {112} planes. The growth axis is the [111] polar direction. Two types of GaP whiskers were grown: straight whiskers and bent whiskers composed of several straight element whiskers. Some of the whiskers contain rotation twins. They are classified into two types: one is rotated around the 〈111〉 growth direction and the other around one of the 〈111〉 directions other than the growth direction.
    Journal of Crystal Growth 08/1988; 91(s 1–2):229–233. DOI:10.1016/0022-0248(88)90390-9 · 1.69 Impact Factor

Publication Stats

154 Citations
14.90 Total Impact Points

Institutions

  • 1988–1999
    • Nagasaki University
      • Department of Marine Material Science
      Nagasaki, Nagasaki, Japan
  • 1992–1998
    • Nagasaki Institute of Applied Science
      Nagasaki, Nagasaki, Japan