研究者業績

本多 信一

ホンダ シンイチ  (Shin-ichi Honda)

基本情報

所属
兵庫県立大学 大学院 工学研究科 電気物性工学専攻 教授
学位
工学(大阪大学)

J-GLOBAL ID
201801013684947136
researchmap会員ID
B000347979

外部リンク

論文

 120
  • A. A. Saranin, A. V. Zotov, M. Kishida, Y. Murata, S. Honda, M. Katayama, K. Oura, D. V. Gruznev, A. Visikovskiy, H. Tochihara
    PHYSICAL REVIEW B 74(3) 2006年7月  査読有り
    Using scanning tunneling microscopy, reversible phase transitions have been detected in the modulated pseudomorphic In monolayer on the Si(111) surface. It has been found that the room-temperature quasihexagonal root 7x root 3 structure is transformed into the root 7x root 7 structure during cooling in the temperature range from 265 to 225 K. Further cooling results in developing long-range modulations in the In layer, including formation of the chevron-type structure with 6 root 7x root 7 periodicity, the ordered arrays with regular antiphase domain boundaries with local 3 root 7x root 7, and 2 root 7x root 7 periodicity and the chained-ring structure with 10/3 root 3x40/3 root 3 periodicity, which is believed to originate from the 5/3 root 3x5/3 root 3 structure occurring at room temperature near surface defects and at domain boundaries of the original root 7x root 3- In phase.
  • S Fujii, Y Michishita, N Miyamae, H Suto, S Honda, H Okado, K Oura, M Katayama
    THIN SOLID FILMS 508(1-2) 82-85 2006年6月  
    The solid-phase reactive epitaxial growth processes and structures of Er/Si(100) thin films were investigated by coaxial impact-collision ion scattering spectroscopy (CAICISS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The as-deposited Er film grown at room temperature was transformed into crystalline rectangular-shaped islands after annealing at 900 degrees C. These islands have a hexagonal AIB(2)-type structure and the epitaxial relationship is determined to be ErSi2(01 (1) over bar0)[0001]//Si(100)[01 (1) over bar]. It has been revealed that the surface of the Er silicide island is terminated with an Er plane. (c) 2005 Elsevier B.V. All rights reserved.
  • Katsunori Aoki, Tetsurou Yamamoto, Hiroshi Furuta, Takashi Ikuno, Shinichi Honda, Mamoru Furuta, Kenjiro Oura, Takashi Hirao
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 45(6A) 5329-5331 2006年6月  
    Thermal-CVD was carried out for the low-temperature growth of carbon nanofibers (CNFs) using a CuNi alloy catalyst film with a thickness of 5 nm on Si in a gas mixture of C2H2 and He (C2H2/He = 3/12 sccm). The experimental results obtained using the CuNi alloy catalyst film were compared with those obtained using the Fe, Ni, and FeNi catalyst films with the same thickness of 5 nm. It was shown that an amorphous CNF with a diameter of 20 urn can be grown even at 400 degrees C using the CuNi catalyst film. but not using the Fe, Ni and FeNi catalysts. A reduction in the growth temperature of CNFs was considered to be achieved using small CuNi catalyst particles with a comparatively smaller surface energy than FeNi catalyst particles.
  • Shin-ichi Honda, Kuei-Yi Lee, Katsunori Aoki, Takashi Hira, Kenjiro Oura, Mitsuhiro Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 45(6A) 5326-5328 2006年6月  
    Vertically aligned carbon nanofiber (CNF) films were successfully grown on glass substrates at 450 degrees C with metal buffer layers by inductively coupled plasma chemical vapor deposition (ICP-CVD). The diameter and number density of the aligned CNFs can be controlled by changing the type and thickness of the metal buffer layers deposited on the glass substrates. The metal buffer layers play an important role in reducing the thermal expansion coefficient difference between the catalyst metal film and the glass substrate, resulting in the enhancement of the formation of catalyst nanoparticles so as to grow the aligned CNFs with high number density.
  • Hirofumi Suto, Shunjiro Fujii, Nobuhiko Miyamae, Robert D. Armitage, Jun Suda, Tsunenobu Kimoto, Shin-ichi Honda, Mitsuhiro Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 45(17-19) L497-L500 2006年5月  
    The surface structure of ZrB2(0001) was investigated using coaxial impact-collision ion scattering spectroscopy (CAICISS). The ZrB2(0001) 1 x 1 surface was prepared by HF solution treatment and annealing in vacuum. It was directly evidenced that the ZrB2(0001) surface is terminated with a Zr layer. Moreover, we found that the interlayer spacing between the first Zr layer and the second B layer is expanded by 20% with regard to c-axis lattice constant. Since small amount of O atoms were detected after the cleaning, the incorporation of the residual O atoms into the subsurface region of the ZrB2(0001) surface is likely to be the origin of the large expansion.
  • T Ikuno, S Honda, K Aoki, K Oura, M Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 45(4A) 2872-2874 2006年4月  
    Standing fibrous carbon nanostructures have been synthesized from graphite substrates without a catalyst using pulsed laser deposition (PLD). Sharpened carbon nanostructures with a diameter of 2-10 nm, a length of 30-180 nm, and a tip angle of 25 degrees were grown on the substrate surface. Transmission electron microscopy revealed that the sharpened carbon nanostructure consists of a few graphite sheets with a good crystallinity. At a low temperature of 500 degrees C, short and conical carbon nanostructures, which are similar to carbon nanohorns, were densely grown at the surface of the graphite substrate.
  • W Wongwiriyapan, S Honda, H Konishi, T Mizuta, T Ikuno, T Ohmori, T Ito, R Shimazaki, T Maekawa, K Suzuki, H Ishikawa, K Oura, M Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 45(4B) 3669-3671 2006年4月  
    We demonstrated ultrasensitive detection of ozone using single-walled carbon nanotube (SWNT) networks directly grown on a conventional sensor substrate. Ozone was detected clown to the ppb level (similar to 6ppb) at room-temperature operation with a fast response. Using an electrical breakdown technique, gas sensitivity was improved. This result clearly indicates that owing to its high sensitivity, simplicity in fabrication and compact size, an SWNT sensor provides a feasible route to ultrasensitive ozone detection surpassing existing methods.
  • Hirofumi Konishi, Shin-Ichi Honda, Masaru Kishida, Yuya Murata, Tatsuro Yasuda, Daisuke Maeda, Kazuhiro Tomita, Kenji Motoyoshi, Shinya Yoshimoto, Rei Hobara, Iwao Matsuda, Jung-Goo Lee, Hirotaro Mori, Kenjiro Oura, Shuji Hasegawa, Mitsuhiro Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 45(4B) 3690-3692 2006年4月  
    Using carbon nanotubes (CNTs) as templates, we have fabricated metal-alloy-coated nanowires by pulsed laser deposition. Superconducting and ferromagnetic materials were uniformly deposited around an isolated multiwalled CNT (MWNT), and reflected the shape of the MWNT. It was found that Nb3Sn and CoFe layers were deposited at a rate of about 0.13 nm/min, which indicates that their film thicknesses can be accurately controlled with nanometer accuracy. We also fabricated a superconductor-coated W tip, and obtained an scanning tunneling microscopy (STM) image of the Au(111) reconstructed surface at 2 K. These results indicate that nanowires synthesized using CNT templates can be used as materials for the tips of a functional scanning probe microscopy (SPM) which provide the nanoscale proximity of superconducting or magnetic nanowires.
  • W Wongwiriyapan, S Honda, T Mizuta, TI Ohmori, T Murakami, K Kisoda, H Harima, JG Lee, H Mori, K Oura, M Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 45(3A) 1880-1882 2006年3月  
    We demonstrated the direct growth of single-walled carbon nanotubes (SWNTs) on a W tip by Fe/Al catalyst-assisted chemical vapor deposition (CVD). A high-purity network of SWNTs with diameters of 0.9-3.7 nm was grown on the W tip. Under optimum CVD conditions, the growth of isolated SWNTs protruding from the W tip apex was achieved. We found that the circumference of the tip region affected the morphology of the resultant SWNTs. The direct growth method provides a potential application of SWNTs to a novel tip for scanning tunnelling microscopy (STM).
  • H Machida, S Honda, S Ohkura, K Oura, H Inakura, M Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 45(2A) 1044-1046 2006年2月  
    We have improved field emission uniformity in a screen-printed paste composed of double-walled carbon nanotubes (DWNTs), which were ground by planetary ball milling (PBM). Results showed that after grinding pristine DWNTs, carbonaceous particles that affected the roughness of the DWNT paste were atomized and long DWNTs were cut. Ground DWNTs were dispersed uniformly on a stainless steel substrate, thereby improving field-emission uniformity. This simple grinding technique is expected to be applicable to low-cost and high-yield processing that produces a DWNT paste for field emitters.
  • M Kishida, Y Murata, D Maeda, H Okado, S Honda, K Oura, M Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 45(1-3) L39-L41 2006年1月  
    The electronic structure of the ZnO(0001)-Zn surface was studied using scanning tunneling spectroscopy (STS) and first principles molecular dynamics. The STS spectrum indicated that the clean surface is n-type semiconducting with a band gap of about 3.3 eV. The local density of states (LDOS) calculated using ZnO slab model was in qualitative agreement with the STS spectrum, and revealed that occupied and unoccupied peaks originate front 0 and Zn atoms at the top bilayer of the surface, respectively. From the contour plots of LDOS, it was found that Zn atoms dominantly contribute to both occupied and unoccupied LDOS distributions and their broadening on the surface, which prevents atom-resolved scanning tunneling microscopy imaging of ZnO(0001) surface.
  • A. A. Saranin, A. V. Zotov, M. Kishida, Y. Murata, S. Honda, M. Katayama, K. Oura, D. V. Gruznev, A. Visikovskiy, H. Tochihara
    Physical Review B - Condensed Matter and Materials Physics 74(3) 2006年  
    Using scanning tunneling microscopy, reversible phase transitions have been detected in the modulated pseudomorphic In monolayer on the Si(111) surface. It has been found that the room-temperature quasihexagonal 7×3 structure is transformed into the 7×7 structure during cooling in the temperature range from 265 to 225 K. Further cooling results in developing long-range modulations in the In layer, including formation of the chevron-type structure with 67×7 periodicity, the ordered arrays with regular antiphase domain boundaries with local 37 ×7, and 27×7 periodicity and the chained-ring structure with 10 3 3× 40 3 3 periodicity, which is believed to originate from the 5 3 3× 5 3 3 structure occurring at room temperature near surface defects and at domain boundaries of the original 7×3-In phase. © 2006 The American Physical Society.
  • A. A. Saranin, A. V. Zotov, I. A. Kuyanov, M. Kishida, Y. Murata, S. Honda, M. Katayama, K. Oura, C. M. Wei, Y. L. Wang
    Physical Review B - Condensed Matter and Materials Physics 74(12) 2006年  
    Using scanning-tunneling microscopy and first-principles total-energy calculations, we have considered the structural properties of the so-called doped clusters formed by depositing additional 0.05 monolayer of In onto the 4×3 -periodicity magic-cluster array in the In/Si(100) system. Low-temperature STM observations have revealed that most of the doped clusters have an asymmetric shape. According to the total-energy calculations, these clusters have plausibly Si6 In8 composition. In such a cluster, one of the In atoms is mobile and can hop between four equivalent sites within a cluster. The hopping between sites, located in the different 2a×3a halves of the cluster, is characterized by the barrier of about 0.7 eV, and this hopping becomes frozen at 55 K. In contrast, the hopping between the neighboring sites within the same cluster half persists up to very low temperatures, as the barrier height here is an order of magnitude lower. Due to the above structural properties, the doped asymmetric Si6 In8 cluster can be treated as a promising switch, logic gate, or memory cell of the atomic-scale size. © 2006 The American Physical Society.
  • Masaru Kishida, Hirofumi Konishi, Yuya Murata, Daisuke Maeda, Tatsuro Yasuda, Takashi Ikuno, Shin-Ichi Honda, Mitsuhiro Katayama, Shinya Yoshimoto, Rei Hobara, Iwao Matsuda, Shuji Hasegawa
    e-Journal of Surface Science and Nanotechnology 3 417-420 2005年12月9日  
    We demonstrated the coating of carbon nanotubes (CNTs) with compound ultrathin films towards functional SPM tips. Conductive, ferromagnetic, and superconducting materials were uniformly coated around isolated multi-walled CNTs (MWNTs). As a conductive probe, the CNT glued on a W tip was wholly coated with a thin PtIr layer 6 nm thick. The current-voltage characteristics of the resultant PtIr-coated CNT tips indicated that the PtIr coating stably reduced the resistance between the CNT tip end and the W supporting tip. Our method will facilitate the development of family of novel functional scanning probe microscopies (SPMs) using CNT tips. © 2005 The Surface Science Society of Japan.
  • T Ikuno, T Yasuda, S Honda, K Oura, M Katayama, JG Lee, H Mori
    JOURNAL OF APPLIED PHYSICS 98(11) 2005年12月  
    Using pulsed laser deposition (PLD), coaxial coating of carbon nanotubes (CNTs) with various inorganic materials (e.g., ZrOx, HfOx, AlOx, ZnOx, and Au) has been performed. The morphology and crystallinity of the coated layers were found to differ according to the materials used even at the same deposition temperature. For oxide materials, the deposits exhibited a uniform layer structure the composition of which was precisely controlled, while for Au, well-crystallized Au nanoparticles were observed on the CNT surface densely. Moreover, not only a single layer but also multiple layers were sequentially coated on CNTs by repeating PLD.
  • W Wongwiriyapan, S Honda, H Konishi, T Mizuta, T Ohmori, T Ito, T Maekawa, K Suzuki, H Ishikawa, T Murakami, K Kisoda, H Harima, K Oura, M Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 44(11) 8227-8230 2005年11月  
    We explored structural and electrical Properties of single-walled carbon nanotube (SWNT) networks directly grown on alumina substrates. The netlike SWNTs were uniformly grown on the substrate at a high quality. From the Raman spectroscopy analysis it was found that the as-grown SWNT networks were a mixture of metallic and semiconducting SWNTs, while the SWNT networks after their electrical breakdown exhibited a predominance of the semiconducting property. The direct growth method and subsequent electrical breakdown facilitated high-throughput production of practical ultrasensitive sensors for pollutant gases with a high sensitivity, which was demonstrated by NO(2) detection.
  • T Ikuno, S Honda, T Yasuda, K Oura, M Katayama, JG Lee, H Mori
    APPLIED PHYSICS LETTERS 87(21) 1-3 2005年11月  
    We observed thermally induced nanomechanical deflection of a hybrid inorganic nanowire (NW) synthesized by pulsed-laser deposition, the structure of which is a carbon nanotube template sandwiched by aluminum oxide and tungsten oxide thin layers. The hybrid NW was gradually bent at a specimen temperature ranging from room temperature to 800 degrees C, due to the different coefficients of thermal expansion of the coated layers. This mechanical deflection exhibited repeatability. (c) 2005 American Institute of Physics.
  • Murata, X, S Yoshimoto, M Kishida, D Maeda, T Yasuda, T Ikuno, S Honda, H Okado, R Hobara, Matsuda, I, S Hasegawa, K Oura, M Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 44(7B) 5336-5338 2005年7月  
    By exploiting the metal coating of carbon nanotube (CNT) tips for a scanning tunneling microscope (STM), we demonstrated atomic imaging/spectroscopy and showed their potential for electrical nanoprobes. A CNT glued to a W tip was uniformly coated with a thin W layer 3-6 nm thick. Using this tip, stable atomic imaging and spectroscopy were carried out on clean Si(111)-7 x 7 and Si(100)-2 x 1 surfaces. The mechanical flexibility of the coated CNT was maintained by virtue of the thin-layer coating, enabling repeated direct contact to the sample surface. Two W-coated CNT tips were brought together within a distance of approximately 50nm. These results indicate that the tips are useful for electronic transport measurements on a nanometer scale after installation into a multiprobe STM.
  • KY Lee, S Honda, M Katayama, T Miyake, K Himuro, K Oura, JG Lee, H Mori, T Hirao
    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 23(4) 1450-1453 2005年7月  
    Vertically aligned carbon nanotubes (CNTs) with long length and high density were successfully synthesized on SiO2, Ta, and Ti substrates by thermal chemical vapor deposition (CVD) The use of Fe catalyst film supported by an Al buffer layer (Fe/Al) has a significant influence on the increase of the number density of the aligned CNTs and the decrease of their diameter. The time dependencies of the aligned CNTs growth show that there is a limit to the length of the aligned CNTs formation. The aligned CNTs can be lengthened further using an intermittent growth method. These findings for the aligned CNTs synthesized on SiO2, Ta, and Ti substrates demonstrate that the thermal intermittent CVD with a Fe/Al multilayer is a versatile method for obtaining vertically aligned CNTs with moderate length, for use in various device applications. (c) 2005 American Vacuum Society.
  • JT Ryu, S Honda, M Katayama, K Oura
    CURRENT APPLIED PHYSICS 5(4) 387-391 2005年5月  
    Using a RF magnetron sputtering, amorphous carbon (a-C) and N-doped a-C (a-C:N) thin films were fabricated as field electron emitter. These thin films were deposited on Si(001) substrate at several temperatures. The field emission property was improved for a-C thin films grown at higher substrate temperatures. Furthermore, a-C:N film exhibits field emission property better than that of undoped a-C film. These results are explained in terms of the change in surface morphology and structural properties of a-C film. (c) 2004 Elsevier B.V. All rights reserved.
  • T Ikuno, S Honda, K Kamada, K Oura, M Katayama
    JOURNAL OF APPLIED PHYSICS 97(10) 2005年5月  
    We have investigated the effect of oxygen addition to methane on the growth of vertically oriented carbon nanotubes (VCNTs) by radio-frequency plasma-enhanced chemical-vapor deposition (RFCVD). By adding moderate concentrations of oxygen to methane during RFCVD, highly crystalline VCNTs were densely grown at 430 degrees C. With increasing oxygen concentration, the length of the VCNTs was increased and the linearity was degraded, whereas when excess oxygen was added to methane, no VCNTs were grown. Plasma states were investigated by optical emission spectroscopy during RFCVD. In the case of RFCVD with oxygen added to methane, peaks due to CO and OH radicals were dominant. The CO species appear to be one of the key factors in the growth of well-crystallized VCNTs. Moreover, VCNTs were grown at temperatures as low as 350 degrees C with the addition of moderate amounts of oxygen to methane in RFCVD. (c) 2005 American Institute of Physics.
  • T Ikuno, S Honda, H Furuta, K Aoki, T Hirao, K Oura, M Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 44(4A) 1655-1660 2005年4月  
    We investigated the influence of the structural properties of randomly oriented carbon nanotube (R-CNT) and vertically oriented carbon nanotube (V-CNT) films on their field electron emission properties. The R-CNT and V-CNT films were synthesized using FeNi catalysts by means of thermal and dual-RF plasma-enhanced chemical vapor depositions, respectively. The structural properties of the R-CNT and V-CNT films were dependent on the initial thickness of the FeNi catalyst. As the FeNi film thickness decreased, the diameters of both types of CNTs decreased. Although the field electron emission property of the V-CNT film was improved with increasing the aspect ratio of V-CNT, the field enhancement factor, beta, obtained from the Fowler-Nordheim plot was found to be 100 times larger than that obtained from the geometric properties. R-CNTs exhibited a lower threshold field than V-CNTs. These results suggest that the field emission property is markedly influenced by the surface state rather than by the geometric factors of CNTs.
  • W Wongwiriyapan, M Katayama, T Ikuno, N Yamauchi, T Mizuta, T Murakami, S Honda, K Oura, K Kisoda, H Harima
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 44(1A) 457-460 2005年1月  
    We explored the growth of single-walled carbon nanotubes (SWNTs) from nanoparticle array made of an Fe/Al multilayer catalyst by thermal chemical vapor deposition. Fe nanoparticles with a high number density and a narrow size distribution (1-5 nm) were efficiently formed by annealing the Fe/Al thin layer, resulting in the high-yield growth of SWNTs. Moreover, it was found that isolated SWNTs are rooted from patterned Fe/Al islands. The SWNTs bridged between electrodes exhibited semiconducting and metallic properties.
  • S Fujii, Y Michishita, N Miyamae, H Suto, S Honda, K Oura, M Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 44(37-41) L1285-L1288 2005年  
    The lattice polarity and relaxation of a ZnO single-crystal (0001) surface were investigated by coaxial impact-collision ion scattering spectroscopy (CAICISS). The angle dependences of Zn intensity were in excellent agreement with a simulation result for a Zn-face bulk structure, with regard to both peak positions and intensity, which is much better than previous works. We use this advantage to determine the degree of surface relaxation quantitatively. It was found that the topmost Zn layer has an inward relaxation of 2% of the c-axis lattice constant.
  • W Wongwiriyapan, S Honda, H Konishi, T Mizuta, T Ikuno, T Ito, T Maekawa, K Suzuki, H Ishikawal, K Oura, M Katayama
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 44(16-19) L482-L484 2005年  
    We demonstrated a gas sensor fabricated by growing a single-walled carbon nanotube (SWNT) thin film directly on a conventional sensor substrate. NO2 and Cl-2 Were detected down to the ppb level under room-temperature operation with a fast response. Using an electrical breakdown technique, gas response sensitivity was improved by an order of magnitude. The relationship between gas concentration and sensor response was derived based on the Langmuir adsorption isotherm, predicting a detection limit of 8 ppb for NO2. The SWNT thin-film gas sensor exhibits merits over other types of sensors by virtue of its simplicity in fabrication and feasible application.
  • S Yoshimoto, Y Murata, R Hobara, Matsuda, I, M Kishida, H Konishi, T Ikuno, D Maeda, T Yasuda, S Honda, H Okado, K Oura, M Katayama, S Hasegawa
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 44(50-52) L1563-L1566 2005年  
    Electrical characteristics of bare and metal-coated carbon nanotube (CNT) tips were investigated with an independently driven four-tip scanning tunneling microscope (STM). The CNT was glued on a W tip apex and wholly coated ex situ by metal thin layers. The resistance between the CNT-tip end and the W supporting tip scattered very widely from ca. 50k Omega to infinity for the bare tips, while coating the tip with a 6-nm-thick PtIr film stably reduced the resistance to less than approximately 10 k Omega. The W coating was also effective for stabilizing the resistance, although they showed slightly larger resistance (ca. 50k Omega). The metal-coated tips kept their low resistance and flexibility even after 100 repeated contacts to an object for conductivity measurements. They are expected to be useful for nanometer-scale transport measurements with multiprobe STM as well as for conventional single-tip STM.
  • KY Lee, S Honda, M Katayama, T Kuzuoka, YG Baek, S Ohkura, K Aoki, T Hirao, K Oura
    THIN SOLID FILMS 464 194-198 2004年10月  
    We synthesized a highly aligned conical Si array on Si(100) for a field electron emitter by plasma-enhanced chemical vapor deposition (PECVD). The number density of these submicron Si cones was controlled in the range 10(6)-10(9) cm(-2). The 10(6) cm(-2) conical Si array exhibited a low threshold voltage for its field electron emission, while for an array with a high number density, the emission property was degraded due to the electric field screening effect. (C) 2004 Elsevier B.V. All rights reserved.
  • S Honda, YG Baek, KY Lee, T Ikuno, T Kuzuoka, JT Ryu, S Ohkura, M Katayama, K Aoki, T Hirao, K Oura
    THIN SOLID FILMS 464 290-294 2004年10月  
    Randomly oriented carbon nanotubes (CNTs) were synthesized directly on SiO2 substrates by thermal chemical vapor deposition (CVD) with C2H4 gas as a carbon source. To control the diameters of the carbon nanotubes, Fe-Ni thin films with different thickness from 80 to 320 nm were deposited as catalysts on SiO2 substrates by magnetron sputtering. The diameter of the resultant carbon nanotubes was dependent on the size of the catalyst particles. Moreover, a small catalyst particle permitted carbon nanotube growth. The resultant randomly oriented carbon nanotubes exhibited good field emission proper-ties. (C) 2004 Elsevier B.V. All rights reserved.
  • R Hobara, S Yoshimoto, T Ikuno, M Katayama, N Yamauchi, W Wongwiriyapan, S Honda, Matsuda, I, S Hasegawa, K Oura
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 43(8B) L1081-L1084 2004年8月  
    The electrical conductance of 0.8 similar to 5-mum-long multiwalled carbon nanotubes (MWCNT) was measured at room temperature in a multiprobe scanning tunneling microscope (STM)-scanning electron microscope (SEM) system and a conventional prober system, by bringing the MWCNTs into contact with patterned metal electrodes. The contact resistance between the CNTs and metal electrodes was sufficiently small. The conductance was proportional to AIL (and also to B/L, within our experimental error), where A, B, and L are the cross,section, circumference, and length of CNTs. This indicates the occurrence of diffusive transport. A nonlinear current-voltage characteristic was obtained; the conductance increased steeply with current. A multiprobe STM-SEM system was very useful for measuring individual CNTs.
  • T Ikuno, M Katayama, KY Lee, T Kuzuoka, JG Lee, S Honda, H Mori, K Oura
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 43(7B) L987-L989 2004年7月  
    We present a method for local etching of the tip region of insulator-coated carbon nanotubes (CNTs) towards passivated nanoprobes. By reactive ion etching (RIE), a 20-nm-thick SiO2 layer, which was uniformly wrapped around vertically oriented CNTs, was selectively removed from the tip, maintaining the crystallinity of inner CNT. It was found that the length of exposed CNT is controlled via etching time at an etching rate of 16 nm/min. This local etching was achieved by RIE using CF4 as an etchant, and photoresist as a passivation mask.
  • M Katayama, KY Lee, S Honda, T Hirao, K Oura
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 43(6B) L774-L776 2004年6月  
    We observed the field electron emission of the technologically useful current density of 10mA/cm(2) at an extremely low threshold electric field (E-th) of 1.0 V/mum, from an array of pillars of aligned carbon nanotube bundles, which were grown on a Si substrate by thermal chemical vapor deposition. Adjusting the distance between the neighboring pillars (R) and the pillar height (H) to the optimal condition (R/H = 2) can effectually enhance the field concentration, resulting in a highly efficient electron emission. The obtained E-th is 1/2-1/3 times lower than the best values that have been reported to date.
  • T Ikuno, M Katayama, M Kishida, K Kamada, Y Murata, T Yasuda, S Honda, JG Lee, H Mori, K Oura
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 43(5A) L644-L646 2004年5月  
    A metal-coated carbon nanotube (CNT) tip for scanning tunneling microscope (STM) has been developed. By pulsed laser deposition (PLD), a CNT attached to a tungsten tip was uniformly coated with 3-6 nm of tungsten thin layer. The observation of a Si(1 1 1)-7 x 7 surface using the tungsten-coated CNT tip demonstrated stable atomic imaging and potentiality of scanning tunneling spectroscopy (STS) measurement, which can be achieved from the pristine stage. It was demonstrated that the mechanical robustness and flexibility of the tip were maintained by virtue of the thin coated layer.
  • KY Lee, S Honda, M Katayama, T Hirao, H Mori, K Oura
    DIAMOND AND RELATED MATERIALS 13(4-8) 1228-1231 2004年4月  
    This study presents a method for controlling the number density of vertically aligned carbon nanotubes (CNTs) by dc bias sputtering. The working gas was the mixture of N-2 and Ne with a total flow rate of 30 sccm. It was found that the number density of aligned CNTs decreased as the content of Ne gas in the gas mixture increased. The field emission properties of aligned CNTs were measured. The lowest threshold electric field of 4.63 V/mum was obtained for the aligned CNTs with a number density of 2.4 X 10(9)/cm(2), which corresponds to 15 sccm of Ne gas. The result shows that there is an optimal number density of aligned CNTs for field emission since the field enhancement factor is affected by a screening factor. (C) 2003 Elsevier B.V. All rights reserved.
  • T Ikuno, M Katayama, N Yamauchi, W Wongwiriyapan, S Honda, K Oura, R Hobara, S Hasegawa
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 43(2) 860-863 2004年2月  
    Carbon nanotubes (CNTs) were grown by low-pressure thermal chemical vapor deposition using pure ethylene. It was found that straight CNTs, which were composed of bundled single- or double-wall CNTs and multiwall CNTs, were preferentially bridged between Fe nanoparticles under a low pressure of 100 Pa. Moreover, utilizing this method, we attempted to grow CNT bridges between patterned Ta electrodes. By nitriding the surface of the Ta electrodes, Fe nanoparticles with a moderate size were effectively formed, resulting in bridging CNTs between the electrodes.
  • T Ikuno, M Kishida, JG Lee, S Honda, M Katayama, H Mori, K Oura
    NANOSENSING: MATERIALS AND DEVICES 5593 18-27 2004年  
    We present a method for synthesizing inorganic-thin-layer-coated carbon nanotubes by pulsed laser deposition. Isolated multi-walled carbon nanotubes (MWNTs) were coated with inorganic thin layer in a multishell form. The product showed that various inorganic thin layers were uniformly wrapped around a MWNT, and reflected the shape of the MWNT. The thickness of the coated thin layer was precisely controlled with nanometer accuracy. Moreover, a metalcoated carbon rianotube (CNT) tip for scanning tunneling microscope (STM) has been developed. The observation of a Si(111)-7x7 surface using the metal-coated CNT tip demonstrated stable atomic imaging and potentiality of scanning tunneling spectroscopy (STS) measurement, which can be achieved from the pristine stage. It was demonstrated that the mechanical robustness and flexibility of the tip were maintained by virtue of the thin coated layer.
  • T Ikuno, M Katayama, K Kamada, S Honda, JG Lee, H Mori, K Oura
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 42(11B) L1356-L1358 2003年11月  
    We present a method for synthesizing insulator-coated carbon nanotubes by pulsed laser deposition. Isolated multi-walled carbon nanotubes (MWNTs) were coated with an SiOx thin layer in a multishell form. The product showed that a stoichiometric SiO2 thin layer was uniformly wrapped around a MWNT, and reflected the shape of the MWNT. The thickness of the SiO2 thin layer was precisely controlled in the range from 2 to 28 nm. The insulating property of the product was verified using a template of vertically oriented carbon nanotubes.
  • K Oura, M Katayama, S Honda, K Lee, N Hayashi, T Hirao, K Endo, M Kimoto, K Nishimura, K Nishio
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 42(10A) L1167-L1170 2003年10月  
    We have successfully developed a method of direct synthesis of carbon nanotubes on catalytic metal substrates, which uses the predeposition of Ti thin layers by thermal chemical vapor deposition. It was found that the amount of carbon nanotubes was dependent on the thickness of the Ti thin layers. We have fabricated a test device of electrochemical double layer capacitors incorporating the grown carbon nanotubes as electrodes, which exhibited stable charge/discharge characteristics.
  • T Ikuno, M Katayama, K Kamada, S Hiwatashi, S Ohkura, S Honda, K Oura
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 42(10) 6717-6720 2003年10月  
    We investigated the correlation between plasma state and structural property in the growth of vertically oriented carbon nanotube (V-CNT) by RF plasma-enhanced chemical vapor deposition (RF-CVD) using pure CH4. The plasma diagnostics in the RF-CVD was performed as a function of RF power using optical emission spectroscopy and self-bias (V-dc) measurement. The structural properties of the grown V-CNT were significantly correlated with the fractions of CH radicals, H atoms or radicals, and V-dc, which were increased with increasing RF power. It was suggested that during V-CNT growth, the H species act as etchants, while the CH radical acts as a precursor of the growth. These antagonistic factors influenced the structural properties of V-CNT, yielding an optimum RF power for the growth of V-CNTs with good crystallinity.
  • T Ikuno, S Takahashi, K Kamada, S Ohkura, S Honda, M Katayama, T Hirao, K Oura
    SURFACE REVIEW AND LETTERS 10(4) 611-615 2003年8月  
    Vertically aligned carbon nanotube (VACNT) films have been grown by RF plasma chemical vapor deposition (RF-PECVD) with a controlling plasma condition. From the in situ optical emission spectroscopy (OES) and self-bias measurements, we have investigated the relationship between the morphology of VACNTs and the plasma condition in PECVD. CH radical and atomic hydrogen peaks were prominent in the OES spectra of CH4 plasma. The plasma condition was changed by varying the interelectrode distance in PECVD. With increasing interelectrode distance, the diameter and density of VACNTs increased as a result of the increase in plasma density, the fraction of CH radicals, and self-bias. It is likely that the fraction of CH radicals in plasma influences promotion of the growth of CNTs, while the self-bias induces their vertical alignment.
  • KY Lee, T Ikuno, K Tsuji, S Ohkura, S Honda, M Katayama, K Oura, T Hirao
    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 21(4) 1437-1441 2003年7月  
    Vertically aligned bamboo-like carbon nanotubes (CNTs) are successfully synthesized on Ni-coated Si (NUSi) substrates by hot-filament-assisted radio frequency (rf) magnetron sputtering. Transmission electron microscopy analysis reveals that a bamboo-like structure is formed inside the nanotube that has a catalytic Ni nanoparticle on the tip. It is likely that moderate carbon particle energy plays an essential role in synthesizing CNTs by sputtering. To verify its importance, we conduct a bias-sputtering experiment to test the effect of negative voltages on the energy of the carbon particles. Furthermore, we find that the diameter and density of the aligned bamboo-like CNTs can be controlled by changing the number density of Ni nanoparticles on Si substrates. (C) 2003 American Vacuum Society.
  • Kuei Yi Lee, Mitsuhiro Katayama, Shin-ichi Honda, Takashi Kuzuoka, Takashi Miyake, Yasuhiro Terao, Jung Goo Lee, Hirotaro Mori, Takashi Hirao, Kenjiro Oura
    Japanese Journal of Applied Physics, Part 2: Letters 42(7B) L804-L806 2003年7月  
    Aligned carbon nanolihers (CNFS) were synlhesi/ed al a growth temperature as low as 200°C by inductively coupled plasma chemical vapor deposition with hydrogen and methane gas mixtures. The synthesized CNFS were aligned perpendicular to the substrate and capped with a single-crystal Ni nanoparticle. The results indicate that the hydrogen species play a significant role in both the reduction ol carbonaceous particles deposits and the formation of catalyst particles by effect ing a moderate etching during the inductively coupled chemical vapor deposition.
  • K Kamada, T Ikuno, S Takahashi, T Oyama, T Yamamoto, M Kamizono, S Ohkura, S Honda, M Katayama, T Hirao, K Oura
    APPLIED SURFACE SCIENCE 212 383-387 2003年5月  
    Carbon nanofiber (CNF) films have been successfully grown on Pd-Se, Fe-Ni, and Ni-Cu alloy catalysts at low temperatures by a thermal chemical vapor deposition method. Among these alloy catalysts, Ni-Cu alloy catalyst was found to be most suitable for low temperature growth of CNF (400 degreesC). Using Pd-Se and Fe-Ni alloy catalysts, CNFs were grown at the lowest temperature of 500 degreesC. The CNFs grown using Pd-Se catalyst were found to have more defective structure than that obtained with the other catalysts, and exhibited excellent field emission property (threshold field is estimated about 1.1 V/mm). It is likely that defects play a role as electron emission sites. (C) 2003 Elsevier Science B.V. All rights reserved.
  • S Honda, YG Baek, T Ikuno, H Kohara, M Katayama, K Oura, T Hirao
    APPLIED SURFACE SCIENCE 212 378-382 2003年5月  
    Silicon carbide (SiC) nanotibers have been synthesized on Si substrates covered by Ni thin films using high power microwave chemical vapor deposition (CVD). Characterization using transmission electron microscopy (TEM) combined with electron energy-dispersive X-ray spectroscopy (EDX) revealed that the resultant fibrous nanostructures were assigned to beta-SiC with high crystallinity. The formation of SiC nanofibers can be explained by the vapor liquid solid (VLS) mechanism in which precipitation of SiC occurs from the supersaturated Ni nanoparticle containing Si and C. (C) 2003 Elsevier Science B.V. All rights reserved.
  • N Hayashi, S Honda, K Tsuji, KY Lee, T Ikuno, K Fujimoto, S Ohkura, M Katayama, K Oura, T Hirao
    APPLIED SURFACE SCIENCE 212 393-396 2003年5月  
    Vertically aligned carbon nanotube (CNT) arrays have been successfully grown on Si substrates by dc bias sputtering. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that the resultant arrays consisted of dense CNTs with diameters of 40-60 nm and lengths of. 300-400 nm. The CNTs were found to have a bamboo-like structure at the end of which metallic nanoparticle was formed, indicating tip growth mechanism. The energy enhancement of carbon particles is a key factor for synthesis of CNTs using dc bias sputtering system. (C) 2003 Elsevier Science B.V. All rights reserved.
  • KJ Cho, JT Ryu, YG Baek, T Ikuno, S Honda, M Katayama, T Hirao, K Oura
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 42(4A) 1744-1748 2003年4月  
    Amorphous carbon (a-C) films were fabricated in pure methane plasma by using the radio frequency plasma-enhanced chemical vapor deposition (RF PECVD) system. Surface morphology and roughness of the films were examined as a function of substrate temperature by atomic force microscopy (AFM). Field emission from the a-C films was examined as a function of substrate, temperature. We found that the roughness and the emission current of the films were improved considerably when the substrate temperature was higher than 600degreesC. From the results obtained by Raman spectroscopy, growth of graphite crystallites was promoted at high substrate temperature. Moreover, the surface morphology was abruptly changed at high substrate temperatures over 600degreesC. We discuss the field emission characteristics of the a-C films with. regard to the surface morphology and the structural features.
  • S Honda, M Katayama, KY Lee, T Ikuno, S Ohkura, K Oura, H Furuta, T Hirao
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 42(4B) L441-L443 2003年4月  
    Inductively coupled plasma chemical vapor deposition combined with substrate biasing using pure methane was applied to low-temperature synthesis of carbon nanotubes. We found that the resultant carbon nanotubes were crystalline even at a growth temperature of 500degreesC. The growth mechanism of the crystallized carbon nanotubes was discussed in terms of the moderate etching of carbon deposit by hydrogen species dissociated from methane in inductively coupled plasma.
  • KY Lee, S Honda, T Ikuno, K Fujimoto, K Tsuji, S Ohkura, M Katayama, T Hirao, K Oura
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 42(2A) 713-715 2003年2月  
    We present a method for aligned bamboolike carbon nanotube (CNT) growth using RF magnetron sputtering. It has been revealed that aligned CNTs can be synthesized by adopting a hot filament in the sputtering system, as demonstrated for CNTs on an Ni/Si substrate. The resultant CNTs were found to be aligned vertically on the substrate with uniform height and have a bamboolike structure. Similar results were obtained for sputtering deposition under a negative sample bias, indicating that the effect of the hot filament can be attributed to the energy enhancement of the carbon particles impinging on the growth front, which plays an essential role in the growth of CNTs by sputtering.
  • YG Baek, S Honda, T Ikuno, S Ohkura, M Katayama, T Hirao, K Oura
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 42(2A) 579-581 2003年2月  
    We have investigated carbon products deposited on large catalyst islands during carbon nanotube growth by thermal chemical vapor deposition on a Fe-Ni catalyst film, using cross-sectional analysis by transmission electron microscopy and scanning electron microscopy. It was found that carbon atoms covering on the surface of Fe-Ni large islands form graphite layers with high crystallinity at a temperature as low as 700degreesC. The growth mechanism of the graphite layers can be explained in terms of precipitation of diffused carbon atoms from the inside of large catalyst islands.
  • Nobuyuki Hayashi, Kuei-Yi Lee, Takashi Ikuno, Keita Tsuji, Shigeharu Ohkura, Shin-Ichi Honda, Mitsuhiro Katayama, Takashi Hirao, Kenjiro Oura
    Shinku/Journal of the Vacuum Society of Japan 46(7) 542-545 2003年  
    We have synthesized highly aligned carbon nanotubcs (CNTs) assembling density-controlled catalyst nanoparricles. The CNTs were grown on Fe or Ni catalyst nanoparticles by RF magnetron sputtering. Structural characterization of the nanoparticles and the CNTs were performed by SEM and TEM. It was found that the densities of both nanoparticles and CNTs were controlled within the ranges of 108∼ 1010/cm2, The density of CNTs almost corresponds to that of the catalyst nanoparticles, and which indicates that the catalyst nanoparticles are the nuclei of the CNTs growth.
  • Takashi Kuzuoka, Yang-Gyu Baek, Takashi Ikuno, Shigeharu Ohkura, Shin-Ichi Honda, Mitsuhiro Katayama, Takashi Hirao, Kenjiro Oura
    Shinku/Journal of the Vacuum Society of Japan 46(3) 302-305 2003年  
    We have developed plasma enhanced chemical vapor deposition system, which can be operated with the low pressure and the low voltage. On the optimal conditions, conical shaped nanostructures with about 1 μm height and 5 × 106 cm-2 in number density were grown on Ni/Si substrate by this system. Furthermore selective growth of conical shaped nanostructures was occurred by using Ni patterned substrate. The obtained conical shaped nanostructures had good emission properties.

MISC

 32

書籍等出版物

 4

講演・口頭発表等

 11

共同研究・競争的資金等の研究課題

 13

産業財産権

 17