The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Hiroshi Kawarada - One of the best experts on this subject based on the ideXlab platform.
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high quality single walled carbon nanotube synthesis using remote Plasma CVD
Diamond and Related Materials, 2012Co-Authors: Toshiyuki Ohashi, Ryogo Kato, Takumi Ochiai, Toshio Tokune, Hiroshi KawaradaAbstract:Abstract Single-walled carbon nanotube (SWNT) forest synthesis using antenna-type remote Plasma chemical vapor deposition (ARPCVD) is presented. A series of synthesis using carbon monoxide gas as carbon feedstock reveals that the remote conditions, in other words, distance between an antenna and a substrate affects the quality of nanotube significantly. That is, far distance geometry on ARPCVD creates high-quality SWNTs. It motivates us to use same methodology for the synthesis using CH4/H2 previously proven to make long SWNT forests. Finally, along the methodology, we achieve to make SWNT forest with high-quality and small diameter successfully. This study offers an important suggestion to embody SWNT forests with both length and quality using remote Plasma CVD.
S. Veprek - One of the best experts on this subject based on the ideXlab platform.
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superhard nc tin a bn and nc tin a tibx a bn coatings prepared by Plasma CVD and pvd a comparative study of their properties
Surface & Coatings Technology, 2003Co-Authors: P Karvankova, Maritza G J Veprekheijman, O Zindulka, A Bergmaier, S. VeprekAbstract:Abstract We present a comparative study of the preparation and properties of superhard ‘Ti–B–N’ coatings deposited by Plasma CVD and by Vacuum Arc Evaporation (PVD) of Titanium combined with Plasma CVD of TiB2 and BN. Using high frequency Plasma CVD at a total pressure of several mbar with TiCl4, BCl3, N2 and H2 as reactants, superhard (HV≈40–50 GPa) nanocomposite coatings were successfully and reproducibly deposited and characterized in terms of mechanical properties (indentation and scanning electron microscope (SEM)), phase composition (X-ray photoelectron spectroscopy and elastic recoil detection) and nanostructure (X-ray diffraction, SEM). Using reactive sputtering, several authors reported about the preparation of superhard TiN/TiB2 coatings with only a small fraction of BN. Efforts to increase the fraction of the BN phase resulted in soft films. In contrast, Plasma CVD yields superhard nc-TiN/a-BN and nc-TiN/a-TiB2/a-BN coatings in a wide range of the fractions of BN and TiB2 phases. This is attributed to the high chemical activity of nitrogen under the conditions of Plasma CVD. Industrial scale vacuum arc evaporation PVD in combination with Plasma CVD is used for preparation of ‘Ti–B–N’ coatings. In the system nc-TiN1−x/a-TiB2 with a minor fraction of the a-BN phase superhard coatings with a very low fraction of microparticles and resultant low surface roughness of Rm≈0.15 μm were successfully prepared and those are intended for testing under a variety of cutting conditions.
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Structural aspects of light emitting nc-Si prepared by Plasma CVD
Journal of Luminescence, 1993Co-Authors: M. Rückschloss, O. Ambacher, S. VeprekAbstract:Abstract We report on the preparation of thin films of light emitting nanocrystalline silicon by Plasma CVD and post-oxidation. The control of the crystalline size allows one to verify theoretical predictions of the increase of the luminescence efficiency with decreasing crystalline size. Some open questions regarding the experimental evidence for the band gap widening are discussed.
Toshiyuki Ohashi - One of the best experts on this subject based on the ideXlab platform.
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high quality single walled carbon nanotube synthesis using remote Plasma CVD
Diamond and Related Materials, 2012Co-Authors: Toshiyuki Ohashi, Ryogo Kato, Takumi Ochiai, Toshio Tokune, Hiroshi KawaradaAbstract:Abstract Single-walled carbon nanotube (SWNT) forest synthesis using antenna-type remote Plasma chemical vapor deposition (ARPCVD) is presented. A series of synthesis using carbon monoxide gas as carbon feedstock reveals that the remote conditions, in other words, distance between an antenna and a substrate affects the quality of nanotube significantly. That is, far distance geometry on ARPCVD creates high-quality SWNTs. It motivates us to use same methodology for the synthesis using CH4/H2 previously proven to make long SWNT forests. Finally, along the methodology, we achieve to make SWNT forest with high-quality and small diameter successfully. This study offers an important suggestion to embody SWNT forests with both length and quality using remote Plasma CVD.
P Karvankova - One of the best experts on this subject based on the ideXlab platform.
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superhard nc tin a bn and nc tin a tibx a bn coatings prepared by Plasma CVD and pvd a comparative study of their properties
Surface & Coatings Technology, 2003Co-Authors: P Karvankova, Maritza G J Veprekheijman, O Zindulka, A Bergmaier, S. VeprekAbstract:Abstract We present a comparative study of the preparation and properties of superhard ‘Ti–B–N’ coatings deposited by Plasma CVD and by Vacuum Arc Evaporation (PVD) of Titanium combined with Plasma CVD of TiB2 and BN. Using high frequency Plasma CVD at a total pressure of several mbar with TiCl4, BCl3, N2 and H2 as reactants, superhard (HV≈40–50 GPa) nanocomposite coatings were successfully and reproducibly deposited and characterized in terms of mechanical properties (indentation and scanning electron microscope (SEM)), phase composition (X-ray photoelectron spectroscopy and elastic recoil detection) and nanostructure (X-ray diffraction, SEM). Using reactive sputtering, several authors reported about the preparation of superhard TiN/TiB2 coatings with only a small fraction of BN. Efforts to increase the fraction of the BN phase resulted in soft films. In contrast, Plasma CVD yields superhard nc-TiN/a-BN and nc-TiN/a-TiB2/a-BN coatings in a wide range of the fractions of BN and TiB2 phases. This is attributed to the high chemical activity of nitrogen under the conditions of Plasma CVD. Industrial scale vacuum arc evaporation PVD in combination with Plasma CVD is used for preparation of ‘Ti–B–N’ coatings. In the system nc-TiN1−x/a-TiB2 with a minor fraction of the a-BN phase superhard coatings with a very low fraction of microparticles and resultant low surface roughness of Rm≈0.15 μm were successfully prepared and those are intended for testing under a variety of cutting conditions.
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Superhard nc-TiN/a-BN and nc-TiN/a-TiBx/a-BN coatings prepared by Plasma CVD and PVD: a comparative study of their properties
Surface & Coatings Technology, 2003Co-Authors: P Karvankova, O Zindulka, A Bergmaier, Maritza G. J. Veprek-heijman, Stan VeprekAbstract:Abstract We present a comparative study of the preparation and properties of superhard ‘Ti–B–N’ coatings deposited by Plasma CVD and by Vacuum Arc Evaporation (PVD) of Titanium combined with Plasma CVD of TiB2 and BN. Using high frequency Plasma CVD at a total pressure of several mbar with TiCl4, BCl3, N2 and H2 as reactants, superhard (HV≈40–50 GPa) nanocomposite coatings were successfully and reproducibly deposited and characterized in terms of mechanical properties (indentation and scanning electron microscope (SEM)), phase composition (X-ray photoelectron spectroscopy and elastic recoil detection) and nanostructure (X-ray diffraction, SEM). Using reactive sputtering, several authors reported about the preparation of superhard TiN/TiB2 coatings with only a small fraction of BN. Efforts to increase the fraction of the BN phase resulted in soft films. In contrast, Plasma CVD yields superhard nc-TiN/a-BN and nc-TiN/a-TiB2/a-BN coatings in a wide range of the fractions of BN and TiB2 phases. This is attributed to the high chemical activity of nitrogen under the conditions of Plasma CVD. Industrial scale vacuum arc evaporation PVD in combination with Plasma CVD is used for preparation of ‘Ti–B–N’ coatings. In the system nc-TiN1−x/a-TiB2 with a minor fraction of the a-BN phase superhard coatings with a very low fraction of microparticles and resultant low surface roughness of Rm≈0.15 μm were successfully prepared and those are intended for testing under a variety of cutting conditions.
Ryogo Kato - One of the best experts on this subject based on the ideXlab platform.
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high quality single walled carbon nanotube synthesis using remote Plasma CVD
Diamond and Related Materials, 2012Co-Authors: Toshiyuki Ohashi, Ryogo Kato, Takumi Ochiai, Toshio Tokune, Hiroshi KawaradaAbstract:Abstract Single-walled carbon nanotube (SWNT) forest synthesis using antenna-type remote Plasma chemical vapor deposition (ARPCVD) is presented. A series of synthesis using carbon monoxide gas as carbon feedstock reveals that the remote conditions, in other words, distance between an antenna and a substrate affects the quality of nanotube significantly. That is, far distance geometry on ARPCVD creates high-quality SWNTs. It motivates us to use same methodology for the synthesis using CH4/H2 previously proven to make long SWNT forests. Finally, along the methodology, we achieve to make SWNT forest with high-quality and small diameter successfully. This study offers an important suggestion to embody SWNT forests with both length and quality using remote Plasma CVD.