The Experts below are selected from a list of 2913 Experts worldwide ranked by ideXlab platform
Shunji Bandow - One of the best experts on this subject based on the ideXlab platform.
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synthesis of carbon nanohorn particles by simple Pulsed Arc discharge ignited between pre heated carbon rods
Chemical Physics Letters, 2004Co-Authors: Takashi Yamaguchi, Shunji Bandow, Sumio IijimaAbstract:Abstract Single-wall carbon nanohorn (SWNH) particles were generated by simple Pulsed Arc discharge between pure carbon rods in the atmospheric pressure of air. Purity of SWNHs was reached higher than 90%, and the heating in dry air at 500 °C was useful for removal of amorphous carbon. The mean size of SWNH particles was ≈50 nm, which is smaller than those prepared by the CO 2 laser method. Pre-heating of the carbon rod up to 1000 °C, conducted just before ignition of Arc, improved the quality of SWNHs. Transmission electron microscopy, scanning electron microscopy and Raman spectroscopy were used to characterize these SWNH particles.
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new synthesis of high quality double walled carbon nanotubes by high temperature Pulsed Arc discharge
Nano Letters, 2003Co-Authors: Toshiki Sugai, Hisanori Shinohara, Hiromichi Yoshida, T Shimada, Toshiya Okazaki, Shunji BandowAbstract:Novel syntheses of high-quality double-walled carbon nanotubes (DWNTs) have been realized by the high-temperature Pulsed Arc discharge method with Y/Ni alloy catalysts at 1250 °C. The optimum conditions of the DWNT synthesis are almost the same as those of single-walled carbon nanotubes (SWNTs), indicating that the growth processes of DWNTs and SWNTs are closely related to each other. High-resolution TEM and Raman spectroscopy have revealed that the present DWNTs have an inner and an outer diameter of 0.8−1.2 and 1.6−2.0 nm, respectively, which correspond to the smallest diameters and the narrowest diameter distribution of mass produced DWNTs ever reported. The purification of the so-produced DWNTs can be achieved by oxidation in air at 500 °C as a result of the remarkable chemical resistance of the current DWNTs compared with that of SWNTs.
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production of fullerenes and single wall carbon nanotubes by high temperature Pulsed Arc discharge
Journal of Chemical Physics, 2000Co-Authors: Toshiki Sugai, Hideki Omote, Shunji Bandow, Nobuo Tanaka, Hisanori ShinoharaAbstract:Fullerenes and single-wall carbon nanotubes (SWNTs) have been produced for the first time by the high-temperature Pulsed Arc-discharge technique, which has developed in this laboratory. Fullerenes are identified quantitatively by high-performance liquid chromatography (HPLC), and scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations reveal a significant amount of production of bundles of SWNTs in soot. The pulse Arc production of fullerenes and SWNTs favors the high-temperature (⩾1000 °C), long pulses (⩾1 ms) and a heavy rare gas such as Ar or Kr as a buffer gas. We have found that fullerenes and SWNTs have complementary relationships in their early stage of production. The details of the Pulsed Arc discharge have been obtained by observing the transition from the Pulsed Arc discharge to the steady Arc discharge while increasing the pulse width.
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PRODUCTION OF SINGLE-WALL NANOTUBES BY HIGH-TEMPERATURE Pulsed Arc DISCHARGE : MECHANISMS OF THEIR PRODUCTION
Japanese Journal of Applied Physics, 1999Co-Authors: Toshiki Sugai, Hideki Omote, Shunji Bandow, Nobuo Tanaka, Hisanori ShinoharaAbstract:Single-wall carbon nanotubes (SWNTs) have been produced for the first time using the high-temperature Pulsed Arc-discharge technique, which has been developed recently in this laboratory, as reported in the conventional steady Arc discharge method. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) observations reveal significant production of bundles of SWNTs in soot. The Pulsed Arc production of SWNTs favors a high-temperature (≥1000°C), long pulses (≥1 ms) and a heavy rare gas such as Ar or Kr as a buffer gas.
Hisanori Shinohara - One of the best experts on this subject based on the ideXlab platform.
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new synthesis of high quality double walled carbon nanotubes by high temperature Pulsed Arc discharge
Nano Letters, 2003Co-Authors: Toshiki Sugai, Hisanori Shinohara, Hiromichi Yoshida, T Shimada, Toshiya Okazaki, Shunji BandowAbstract:Novel syntheses of high-quality double-walled carbon nanotubes (DWNTs) have been realized by the high-temperature Pulsed Arc discharge method with Y/Ni alloy catalysts at 1250 °C. The optimum conditions of the DWNT synthesis are almost the same as those of single-walled carbon nanotubes (SWNTs), indicating that the growth processes of DWNTs and SWNTs are closely related to each other. High-resolution TEM and Raman spectroscopy have revealed that the present DWNTs have an inner and an outer diameter of 0.8−1.2 and 1.6−2.0 nm, respectively, which correspond to the smallest diameters and the narrowest diameter distribution of mass produced DWNTs ever reported. The purification of the so-produced DWNTs can be achieved by oxidation in air at 500 °C as a result of the remarkable chemical resistance of the current DWNTs compared with that of SWNTs.
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production of fullerenes and single wall carbon nanotubes by high temperature Pulsed Arc discharge
Journal of Chemical Physics, 2000Co-Authors: Toshiki Sugai, Hideki Omote, Shunji Bandow, Nobuo Tanaka, Hisanori ShinoharaAbstract:Fullerenes and single-wall carbon nanotubes (SWNTs) have been produced for the first time by the high-temperature Pulsed Arc-discharge technique, which has developed in this laboratory. Fullerenes are identified quantitatively by high-performance liquid chromatography (HPLC), and scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations reveal a significant amount of production of bundles of SWNTs in soot. The pulse Arc production of fullerenes and SWNTs favors the high-temperature (⩾1000 °C), long pulses (⩾1 ms) and a heavy rare gas such as Ar or Kr as a buffer gas. We have found that fullerenes and SWNTs have complementary relationships in their early stage of production. The details of the Pulsed Arc discharge have been obtained by observing the transition from the Pulsed Arc discharge to the steady Arc discharge while increasing the pulse width.
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Production of fullerenes by high-temperature Pulsed Arc discharge
European Physical Journal D, 1999Co-Authors: Toshiki Sugai, Hideki Omote, Hisanori ShinoharaAbstract:We have developed a high-temperature Pulsed Arc discharge apparatus, which can operate in a buffer gas heated up to 1000 °C, and have succeeded in producing fullerenes for the first time with this method. We have quantitatively analyzed the products, using high-performance liquid chromatography (HPLC), to estimate the concentration of fullerenes in soot. The results show that fullerenes are produced not at room temperature but at much higher temperatures such as 1000 °C for Ar. The concentration of fullerenes C70 and higher increases as the pulse width of the discharge increases. In the Pulsed Arc discharge, the negative electrode is consumed by the sputtering of buffer gas ions.
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PRODUCTION OF SINGLE-WALL NANOTUBES BY HIGH-TEMPERATURE Pulsed Arc DISCHARGE : MECHANISMS OF THEIR PRODUCTION
Japanese Journal of Applied Physics, 1999Co-Authors: Toshiki Sugai, Hideki Omote, Shunji Bandow, Nobuo Tanaka, Hisanori ShinoharaAbstract:Single-wall carbon nanotubes (SWNTs) have been produced for the first time using the high-temperature Pulsed Arc-discharge technique, which has been developed recently in this laboratory, as reported in the conventional steady Arc discharge method. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) observations reveal significant production of bundles of SWNTs in soot. The Pulsed Arc production of SWNTs favors a high-temperature (≥1000°C), long pulses (≥1 ms) and a heavy rare gas such as Ar or Kr as a buffer gas.
Bernd Schultrich - One of the best experts on this subject based on the ideXlab platform.
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High-yield synthesis of single-walled carbon nanotubes with a Pulsed Arc-discharge technique
Physica Status Solidi B-basic Solid State Physics, 2007Co-Authors: Aljoscha Roch, Bernd Schultrich, O. Jost, Eckhard BeyerAbstract:This contribution deals with the synthesis of Single-Walled Carbon Canotubes (SWCNT) with a novel Pulsed Arc-discharge technique. Pulsed Arc-discharge is a very interesting technique because it is similar to the well-known laser evaporation technique for the synthesis of SWCNT and should allow a scale-up to reach a SWCNT volume production. We performed a number of experiments to find optimal conditions for the Arc-based SWCNT synthesis. The obtained data have been compared with known results from laser evaporation synthesis of SWCNT. The results indicate that it is possible to get specifically optimized synthesis conditions for the Arc-discharge method that are very similar to that of the laser evaporation synthesis. Both methods allow to get similar nanotube qualities (high yield, narrow diameter distribution). We discuss similarities in the formation mechanisms between both methods.
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Pulsed Arc deposition of super hard amorphous carbon films
Applied Physics A, 2004Co-Authors: H Schulz, Peter Siemroth, H J Scheibe, Bernd SchultrichAbstract:Hydrogen-free amorphous carbon films with hardness up to 75 GPa have been deposited by special Pulsed Arc techniques. The influence of plasma and deposition conditions on the film properties is discussed and some applications are shown.
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Comparison of filtered high-current Pulsed Arc deposition (φ-HCA) with conventional vacuum Arc methods
Surface & Coatings Technology, 2000Co-Authors: T. Witke, Peter Siemroth, Bernd Schultrich, Thomas Schuelke, Jörg VetterAbstract:Abstract Special features of the filtered high-current Pulsed Arc deposition (φ-HCA) are presented in comparison with the conventional dc-Arc method. The high-current Arc technique allows pulse currents of some kiloamperes and averaged Arc currents of approximately 1 kA. Due to the high spot velocity the droplet density is already markedly reduced. The remaining particles may be completely eliminated by combination with a magnetic filter. The optimum design of this device together with the high efficiency of the Pulsed Arc source yields ion currents at the filter exit above 100 A during a Pulsed Arc and above 10-A averaged current. High quality films with deposition rates of industrial relevance may be produced by advanced Arc techniques. Various coatings such as metal refractory nitrides, oxides and hard coatings are investigated and compared with the conventional dc-Arc deposition. It is shown that the φ-HCA module is a promising supplementary device that can be attached to industrial standard equipment for various applications demanding smooth mirror-like metallic hard coatings.
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Gap filling with high current Pulsed Arc evaporation: influence of deposition parameters
European Workshop Materials for Advanced Metallization, 1997Co-Authors: Wolfgang Klimes, C. Wenzel, Peter Siemroth, Bernd SchultrichAbstract:Summary form only given. The presentation focuses on new and more detailed results of the high current Pulsed Arc evaporation technique (HCA) used for trench and via filling in aluminum and copper based multilevel metallization systems. Besides PVD-based filling techniques like Al force fill, copper reflow, copper self-sputtering or ICP/ECR-based ionised sputtering, the HCA deposition technique is performed and modified to reach void free filled vias and trenches with an increasing aspect ratio. The results show that this PVD technique can be compared with the above-mentioned filling methods. Furthermore, the potential of this method seems to be broader due to the very high ionization level and a kinetic energy of the ions up to 100 eV. It is possible to realize both a nearly conformal deposition and a via filling without sufficiently covering the top of the substrate surface.
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Deposition of superhard amorphous carbon films by Pulsed Arc sources
IEEE Transactions on Plasma Science, 1997Co-Authors: H J Scheibe, Bernd Schultrich, H. Ziegele, Peter SiemrothAbstract:Hydrogen-free amorphous carbon films with hardness comparable to crystalline superhard materials have been deposited by special Pulsed Arc techniques. With the combination of very high hardness, high smoothness, and low adhesion activity to other materials which are in contact with them, these films show superior behavior in wear and slide applications. The influence of plasma and deposition conditions on these film properties and the choice of optimum conditions are discussed.
Toshiki Sugai - One of the best experts on this subject based on the ideXlab platform.
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new synthesis of high quality double walled carbon nanotubes by high temperature Pulsed Arc discharge
Nano Letters, 2003Co-Authors: Toshiki Sugai, Hisanori Shinohara, Hiromichi Yoshida, T Shimada, Toshiya Okazaki, Shunji BandowAbstract:Novel syntheses of high-quality double-walled carbon nanotubes (DWNTs) have been realized by the high-temperature Pulsed Arc discharge method with Y/Ni alloy catalysts at 1250 °C. The optimum conditions of the DWNT synthesis are almost the same as those of single-walled carbon nanotubes (SWNTs), indicating that the growth processes of DWNTs and SWNTs are closely related to each other. High-resolution TEM and Raman spectroscopy have revealed that the present DWNTs have an inner and an outer diameter of 0.8−1.2 and 1.6−2.0 nm, respectively, which correspond to the smallest diameters and the narrowest diameter distribution of mass produced DWNTs ever reported. The purification of the so-produced DWNTs can be achieved by oxidation in air at 500 °C as a result of the remarkable chemical resistance of the current DWNTs compared with that of SWNTs.
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production of fullerenes and single wall carbon nanotubes by high temperature Pulsed Arc discharge
Journal of Chemical Physics, 2000Co-Authors: Toshiki Sugai, Hideki Omote, Shunji Bandow, Nobuo Tanaka, Hisanori ShinoharaAbstract:Fullerenes and single-wall carbon nanotubes (SWNTs) have been produced for the first time by the high-temperature Pulsed Arc-discharge technique, which has developed in this laboratory. Fullerenes are identified quantitatively by high-performance liquid chromatography (HPLC), and scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations reveal a significant amount of production of bundles of SWNTs in soot. The pulse Arc production of fullerenes and SWNTs favors the high-temperature (⩾1000 °C), long pulses (⩾1 ms) and a heavy rare gas such as Ar or Kr as a buffer gas. We have found that fullerenes and SWNTs have complementary relationships in their early stage of production. The details of the Pulsed Arc discharge have been obtained by observing the transition from the Pulsed Arc discharge to the steady Arc discharge while increasing the pulse width.
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Production of fullerenes by high-temperature Pulsed Arc discharge
European Physical Journal D, 1999Co-Authors: Toshiki Sugai, Hideki Omote, Hisanori ShinoharaAbstract:We have developed a high-temperature Pulsed Arc discharge apparatus, which can operate in a buffer gas heated up to 1000 °C, and have succeeded in producing fullerenes for the first time with this method. We have quantitatively analyzed the products, using high-performance liquid chromatography (HPLC), to estimate the concentration of fullerenes in soot. The results show that fullerenes are produced not at room temperature but at much higher temperatures such as 1000 °C for Ar. The concentration of fullerenes C70 and higher increases as the pulse width of the discharge increases. In the Pulsed Arc discharge, the negative electrode is consumed by the sputtering of buffer gas ions.
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PRODUCTION OF SINGLE-WALL NANOTUBES BY HIGH-TEMPERATURE Pulsed Arc DISCHARGE : MECHANISMS OF THEIR PRODUCTION
Japanese Journal of Applied Physics, 1999Co-Authors: Toshiki Sugai, Hideki Omote, Shunji Bandow, Nobuo Tanaka, Hisanori ShinoharaAbstract:Single-wall carbon nanotubes (SWNTs) have been produced for the first time using the high-temperature Pulsed Arc-discharge technique, which has been developed recently in this laboratory, as reported in the conventional steady Arc discharge method. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) observations reveal significant production of bundles of SWNTs in soot. The Pulsed Arc production of SWNTs favors a high-temperature (≥1000°C), long pulses (≥1 ms) and a heavy rare gas such as Ar or Kr as a buffer gas.
Peter Siemroth - One of the best experts on this subject based on the ideXlab platform.
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Pulsed Arc deposition of super hard amorphous carbon films
Applied Physics A, 2004Co-Authors: H Schulz, Peter Siemroth, H J Scheibe, Bernd SchultrichAbstract:Hydrogen-free amorphous carbon films with hardness up to 75 GPa have been deposited by special Pulsed Arc techniques. The influence of plasma and deposition conditions on the film properties is discussed and some applications are shown.
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Comparison of filtered high-current Pulsed Arc deposition (φ-HCA) with conventional vacuum Arc methods
Surface & Coatings Technology, 2000Co-Authors: T. Witke, Peter Siemroth, Bernd Schultrich, Thomas Schuelke, Jörg VetterAbstract:Abstract Special features of the filtered high-current Pulsed Arc deposition (φ-HCA) are presented in comparison with the conventional dc-Arc method. The high-current Arc technique allows pulse currents of some kiloamperes and averaged Arc currents of approximately 1 kA. Due to the high spot velocity the droplet density is already markedly reduced. The remaining particles may be completely eliminated by combination with a magnetic filter. The optimum design of this device together with the high efficiency of the Pulsed Arc source yields ion currents at the filter exit above 100 A during a Pulsed Arc and above 10-A averaged current. High quality films with deposition rates of industrial relevance may be produced by advanced Arc techniques. Various coatings such as metal refractory nitrides, oxides and hard coatings are investigated and compared with the conventional dc-Arc deposition. It is shown that the φ-HCA module is a promising supplementary device that can be attached to industrial standard equipment for various applications demanding smooth mirror-like metallic hard coatings.
-
Gap filling with high current Pulsed Arc evaporation: influence of deposition parameters
European Workshop Materials for Advanced Metallization, 1997Co-Authors: Wolfgang Klimes, C. Wenzel, Peter Siemroth, Bernd SchultrichAbstract:Summary form only given. The presentation focuses on new and more detailed results of the high current Pulsed Arc evaporation technique (HCA) used for trench and via filling in aluminum and copper based multilevel metallization systems. Besides PVD-based filling techniques like Al force fill, copper reflow, copper self-sputtering or ICP/ECR-based ionised sputtering, the HCA deposition technique is performed and modified to reach void free filled vias and trenches with an increasing aspect ratio. The results show that this PVD technique can be compared with the above-mentioned filling methods. Furthermore, the potential of this method seems to be broader due to the very high ionization level and a kinetic energy of the ions up to 100 eV. It is possible to realize both a nearly conformal deposition and a via filling without sufficiently covering the top of the substrate surface.
-
Deposition of superhard amorphous carbon films by Pulsed Arc sources
IEEE Transactions on Plasma Science, 1997Co-Authors: H J Scheibe, Bernd Schultrich, H. Ziegele, Peter SiemrothAbstract:Hydrogen-free amorphous carbon films with hardness comparable to crystalline superhard materials have been deposited by special Pulsed Arc techniques. With the combination of very high hardness, high smoothness, and low adhesion activity to other materials which are in contact with them, these films show superior behavior in wear and slide applications. The influence of plasma and deposition conditions on these film properties and the choice of optimum conditions are discussed.
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Deposition of superhard amorphous carbon films by Pulsed Arc sources
Proceedings of 17th International Symposium on Discharges and Electrical Insulation in Vacuum, 1996Co-Authors: H J Scheibe, Bernd Schultrich, H. Ziegele, Peter SiemrothAbstract:Hydrogen-free amorphous carbon films with hardness comparable to crystalline superhard materials have been deposited by special Pulsed Arc techniques. By the combination of very high hardness, low adhesion and high smoothness, these films show superior behaviour in wear and glide applications. The influence of plasma and deposition conditions on these film properties and the choice of optimum conditions are discussed.
