Cheow Keong CHOO

International Education CenterProfessor
  • Profile:

    My research field is to discover new materials for electronic devices and photo-luminescence devices. I have also done experimental research on synthesis and analysis of silicon nanoparticles/clusters en-captured in Zeolite porous.

Degree

  • Master of Engineering, The University of Electro-Communications, Mar. 1997
  • Dotor of Engineering, The University of Electro-Communications, Mar. 2000

Research Keyword

  • Optical properties
  • Research and development
  • Electron and emission
  • Electronic properties in general
  • Science and technology in general
  • Solid-state devices
  • Engineering in general
  • 光物性
  • 研究開発
  • イオン放出
  • 電子放出
  • 電子物性一般
  • 科学技術一般
  • 固体デバイス
  • 工学一般

Field Of Study

  • Nanotechnology/Materials, Applied physics - general, Nano Science, Material Science, Applied Physics, Electronics

Educational Background

  • Apr. 1997 - Mar. 2000
    The University of Electro-Communications, Graduate School, Division of Electro Communications (Doctor), Department of Electronic Engineering, Japan
  • Apr. 1995 - Mar. 1997
    The University of Electro-Communications, Graduate School, Division of Electro Communications (Master), Department of Electronic Engineering, Japan
  • Apr. 1991 - Mar. 1995
    The University of Electro-Communications, Faculty of Electro Communications, Department of Electronic Engineering, Japan

Member History

  • Jun. 2021 - Present
    国費特別プログラム実施委員, 電気通信大学
  • Nov. 2020 - Present
    国際教育WG, 電気通信大学
  • Apr. 2017 - Present
    大学院 情報理工学研究科 教育委員, 電気通信大学, 国際教育センターからオブザーバーとして参加
  • Apr. 2013 - Present
    国際交流センター運営委員会, 電気通信大学
  • Apr. 2009 - Present
    研究設備センター委員
  • Dec. 2019 - May 2021
    拡大MICH運営委員, 電気通信大学
  • Apr. 2010 - Mar. 2014
    安全・環境保全室(薬品管理部門), 電気通信大学
  • Apr. 2002 - Mar. 2005
    機器分析センター委員, 電気通信大学

Paper

  • The University of Electro-Communications International Courses - UEC Academic Skills I (Computer Literacy) -
    CHOO Cheow Keong
    Lead, The Tama Bulletin of International Student Education, 11, 16-23, Mar. 2018, Peer-reviwed, False, The University of Electro-Communications (UEC) has designed a series of international courses in 1997, which aim to meet the educational goal of internationalizing the student body and to strengthen student’s English skills. These international courses are also offered to the oversea short-term exchange students, providing opportunities to both the regular students and short-term exchange students to interact and learn from each other. UEC Academic Skills I (Computer Literacy) is one of the international course being offered for undergraduate, to acquire computer skills, to facilitate active communication between regular students and short-term exchange students, and simultaneously provides an environment to incentivize the regular students to pursue a study abroad. In this paper, we report on the curriculum contents of UEC Academic Skills I, whose content has been revised in conjunction with the reorganization of the international courses in 2014. A course evaluation by students has been conducted and analyzed in order to spot the problems, and to improve the course's delivery approach and quality.
    Scientific journal, Japanese
  • Characterization of SrTiO3 target doped with Co ions, SrCoxTi1-xO3-delta, and their thin films prepared by pulsed laser ablation (PLA) in water for visible light response
    Fumihiko Ichihara; Yuma Murata; Hiroshi Ono; Cheow-keong Choo; Katsumi Tanaka
    APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 419, 126-137, Oct. 2017, Peer-reviwed, SrTiO3 (STO) and Co-doped SrTiO3 (Co-STO) sintered targets were synthesized and were Ar+ sputtered to elucidate the charge compensation effect between Sr, Ti and Co cations following the reduction by oxygen desorption. Following exposure of the Ar+-sputtered target to the air, charge transfer reactions occurred among Co2+, Ti3+, O2- and Sr2+ species which were studied by their XPS spectra. Pulsed laser ablation (PLA) of these targets was carried out in water to prepare the nanoparticles which could be supplied to the thin films with much higher surface reactivity expected for photocatalytic reactions. The roles of Co ions were studied for the stoichiometry and crystallinity of the nanoparticles which constituted the thin films. Photo-degradation of methylene blue was carried out on the PLA thin films under very weak visible light at 460 nm. The PLA thin films showed the photocatalytic activities, which were enhanced by the presence of Co ions. Such the effect of Co ions was considered from viewpoint of the d-d transition and the charge-transfer between Co ions and the ligand oxygen. (C) 2017 Published by Elsevier B.V.
    Scientific journal, English
  • Effects of nitrogen substitution in amorphous carbon films on electronic structure and surface reactivity studied with x-ray and ultra-violet photoelectron spectroscopies
    Yuma Murata; Rempei Nakayama; Fumihiko Ichihara; Hiroshi Ono; Cheow-Keong Choo; Katsumi Tanaka
    JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 121, 9, 095302-1-095302-12, Mar. 2017, Peer-reviwed, We investigated the effects of incorporating a low percentage of nitrogen on the local and the electronic structures of amorphous carbon (a-C) using X-ray photoelectron spectroscopy and ultra-violet photoelectron spectroscopy (UPS). Nitrogen-doped amorphous carbon films (a-CNx) with varying nitrogen contents were prepared by a thermal decomposition method using a mixture of CH4 + NH3 under atmosphere. A slight shift of the C 1s core-level spectrum toward the higher binding energy side was detected in a-CNx as a function of nitrogen content, whereas a shift of the Fermi level (E-F) cannot be confirmed from the UPS results. This was interpreted as a chemical shift between carbon and nitrogen atoms rather than as a shift of the E-F. The C 1s peak shifts can be explained by the presence of two kinds of C-N local structures and the charge transferred bulk C-C components by nitrogen atoms. The two kinds of deconvoluted C 1s components could be well correlated with the two N 1s components. Two localized states were detected below the E-F in UPS spectra of a-CNx, which could be assigned to defect bands. These defects played a significant role in the surface reactivity, and were stabilized in a-CNx. The adsorption and reaction of NO were carried out on a-CNx as well as a-C films. It was found that both defect sites and O2- species were responsible on a-C, while O2- species were selectively active for NO adsorption on a-CNx. We concluded that nitrogen doping reduces defect density to stabilize the surface of a-C, while at the same time inducing the selective adsorption capability of NO. Published by AIP Publishing.
    Scientific journal, English
  • The Construction and Management of the Safety Confirmation System for Foreign Student by Using Moodle
    CHOO Cheow Keong
    The Tama Bulletin of International Student Education, 電気通信大学国際交流推進センター ; 2006-, 10, 23-29, Mar. 2016, Peer-reviwed
    Scientific journal, Japanese
  • Characterization of N-doped DLC thin films prepared by hydrocarbons pyrolysis method
    Yuma Murata; Cheow-Keong Choo; Hiroshi Ono; Yutaka Nagai; Katsumi Tanaka
    MATERIALS TODAY-PROCEEDINGS, ELSEVIER SCIENCE BV, 3, S197-S202, 2016, Peer-reviwed, Nitrogen-doped DLC thin films prepared by a hydrocarbons pyrolysis method were characterized with Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy and a four-terminal current-voltage measuring method in terms of their structural, bonding, optical and electrical properties. Raman spectra showed that doping N atoms in the DLC films caused the full width at half maximum (FWHM) values of G-peak to be broader, the G-peak positions to shift downward and the I-D/I-G ratio to be lower than non-doped DLC films. These indicate that N-doping to DLC induces the reduction of the sp(2) based nanocluster size. The chemical bonding state of the N-doped DLC films was homogeneous in bulk, which was evaluated with XPS by Ar sputtering of the DLC films. The XPS spectra of C1s and N1s showed that the hybridized C ratio (sp(3)C/sp(2)C) of the deconvoluted C1s spectra increased due to the formation of the N bonded to sp(3)C (N-sp(3)C). In addition, the optical band gap and the resistance increased by doping N atoms in the DLC films. Our experimental results show that N-doping leads to an increase of the sp(3)C/sp(2)C and the resistance as well as the optical band gap of the DLC films prepared with the hydrocarbons pyrolysis method. (C) 2016 The Authors. Published by Elsevier Ltd.
    International conference proceedings, English
  • Introduction of Conference Management System (CMS) for UEC Academic Skills Class
    CHOO Cheow Keong
    The Tama Bulletin of International Student Education, 電気通信大学国際交流推進センター, 9, 61-65, Mar. 2014, Peer-reviwed
    Scientific journal, Japanese
  • 先進理工学科における2年次専門実験(電気・電子回路実験)の準備と実施について
    奥野剛史; 大家明広; 山崎典昌; 高橋光生; 早川義彦; 矢崎和幸; 和田紀子; 藁科崇; 坂本克好; Choo Cheow Keong; 永井豊; 守屋雅隆; 沈青; 島田宏; 林茂雄
    電気通信大学紀要, 電気通信大学, 25, 1, 73-78, Feb. 2013, Peer-reviwed, The new laboratory class of Electric and Electronic Circuit Laboratory has been conducted. All of the second year students at the Department of gineering Science are required to take this class. An example of preparation for new classes in the new department is shown. Academic engineers and faculties formerly belonging to dif ferent depar tments are cooperatively involved in the preparation and teaching for the laboratory class. The class has been successfully completed in 2011 for the first time after the reorganization of the Faculty of Informatics and Engineering in April 2010. The results concerning report scores of students, answers of students' questionnaires, and e-Learning are shown and discussed.
    Research institution, Japanese
  • Deposition of potassium-oxygen on silicon surfaces by pulsed laser ablation of potassium superoxide: Study of work function changes
    CK Choo; D Suzawa; K Tanaka
    SURFACE SCIENCE, ELSEVIER SCIENCE BV, 600, 7, 1518-1525, Apr. 2006, Peer-reviwed, Potassium-oxygen species were deposited on pure, Si nanoparticles coated and H-terminated Si nanoparticles coated p-Si(1 0 0) surfaces by pulsed laser ablation of potassium superoxide (KO,) target. The deposition properties, composition and the work function changes of the deposited species were investigated in situ using an X-ray photoelectron spectroscopy (XPS) and a Kelvin probe measurement. The deposited species were assigned to K2O2 and KO2, and they can be selectively deposited by controlling the laser fluence: i.e., at 200 mJ/cm(2) and at those more than 300 mJ/cm(2) respectively. Experimental results showed that the work function decreased drastically with depositing of KOx (x = 1 or 2), and the minimum work function values observed were 1.0 eV and 0.7 eV for pure p-Si(1 0 0) and Si nanoparticles coated substrates, respectively. The study demonstrates the formation of the surface species with minimum work function can be identified by XPS. (c) 2006 Elsevier B.V. All rights reserved.
    Scientific journal, English
  • Time-resolved photoluminescence spectra of Si species encapsulated in zeolite supercages
    K Tanaka; Y Komatsu; CK Choo
    JOURNAL OF PHYSICAL CHEMISTRY B, AMER CHEMICAL SOC, 109, 2, 736-742, Jan. 2005, Peer-reviwed, Photoluminescence (PL) spectra of Si species encapsulated in zeolite supercages are studied. It is reported that the chained Si species terminated partially with phenyl groups and with some unsaturated bonds are formed in zeolite supercages by the reaction with phenylsilane and they show PL around 4 eV (J. Phys. Chem. 2004, 108, 2501-2508). In the present paper they are reduced with hydrogen to prepare Si chained species terminated and saturated with hydrogen atoms. The PL spectra are deconvoluted to be four components at 1.9, 2.2, 2.6, and 3.7 eV, which can tentatively be assigned to Si nanocrystals and Si quantum wires in addition to defects in SiO(2) and uncontrolled organic impurities in zeolite, respectively. At elevated temperatures the Si quantum wires in zeolite pores seem to change the Si nanocrystals with the size larger than that of the zeolite pore diameter. It is the first case in which the PL decay lifetime of oxygen vacancies in zeolite can be detected to be quite short to be about 16 ns. The detected lifetimes of Si quantum wires are significantly very short, about 12 ns. The Si species encapsulated zeolite is solvated with hydrofluoric acid solution to separate the Si quantum wires by dissolving zeolite lattice. The Si quantum wires in the HF solution show intense PL spectra peaked at 2.33 eV and broad UV spectra around 2.8-3.5 eV. They will have different shapes and lengths. The HF solvated zeolite shows still PL spectra characteristic of oxygen vacancies and the absorption edge at 3.6 eV. The result means that zeolite lattice is solvated in HF solution as clusters with a band gap of 3.6 eV and they can still have some oxygen vacancies. Oxygen vacancies situate about 1.0 eV below the zeolite conduction band minimum, and the absorbed energy can be dissipated as PL between the valence band maximum and the oxygen vacancies. It is concluded that the excitation photon energy can be absorbed in zeolite and the Si quantum wires and then the absorbed energies are competitively relaxed in zeolite and the Si quantum wires.
    Scientific journal, English
  • Titania nanoparticles prepared with pulsed laser ablation of rutile single crystals in water
    A Iwabuchi; CK Choo; K Tanaka
    JOURNAL OF PHYSICAL CHEMISTRY B, AMER CHEMICAL SOC, 108, 30, 10863-10871, Jul. 2004, Peer-reviwed, The pulsed laser ablation (PLA) experiments of rutile single crystal surfaces were carried out in water solution to prepare nanosized titania particles. The solvated PLA species were transparent as produced and changed to a lighter blue solution with some precursors for filamentous species (in several days), then finally changed to white enlarged filamentous species (in 2-4 weeks). The solvated PLA species were measured as uniform nanoparticles with a size below 10 nm by TEM measurements and showed the absorption-photon energy relation for the direct transition with a band gap of 5.3-5.5 eV. The band-gap values were elucidated with quantum confinement size effects. It was assumed that the primary solvated species should have a size of about 1 nm and they were agglomerated to be the secondary species. The Mie scattering is responsible for the "blue" color, which proves that the size enlargement process exists on the PLA species in water. The filamentous species are composed of mainly the anatase form, which was analyzed with Raman spectroscopy. The XPS results indicate that the Ti species are tetravalent and bonded to oxygen atoms with O 1s binding energy at around 530 eV as TiO2. They were found to be composed to about 1 mum diameter with gathering nanosized particles on SEM pictures. The thin films composed of the PLA filamentous species showed no band cap increase. The process for PLA of rutile in water was studied with different temperatures (T in K) to elucidate the effect of viscosity (eta). The yield of PLA species in water decreases nearly linearly with the ratio of T/eta representing the diffusion coefficient of the solvated species. The result implies that the PLA species are confined in a media not diffused into water solution.
    Scientific journal, English
  • Photoluminescence intensity enhancement of ion-doped CdWO4 thin films prepared with pulsed laser deposition
    CK Choo; S Suzuki; K Tanaka
    THIN SOLID FILMS, ELSEVIER SCIENCE SA, 458, 1-2, 179-185, Jun. 2004, Peer-reviwed, Samarium-, nickel- and cesium-ion doped CdWO4 thin films as well as non-doped CdWO4 thin films were prepared by the pulsed laser deposition (PLD) method. The film thickness and the substrate temperature during PLD were changed to study the role of doped ions on the CdWO4 lattice. The crystalline CdWO4 thin films were obtained by PLD on glass substrates at 1073 K. The CdWO4 (002) XRD signal was more intense on the non-doped, Sm- and Ni-doped PLD films. When the substrate temperature was increased to 1273 K, the peak decreased in intensity, and the (111) peak became more intense than the intensity of the (002) on the ion-doped PLD films whereas the (020) signal was still significant on the non-doped thin film. Photoluminescence spectra were deconvoluted into three components at 2.82, 2.54 and 2.27 eV The contribution of the yellow PL component at 2.27 eV was relatively high on the doped PLD films prepared at 1073 K. However, the overall PL spectra features on PLD films prepared at 1273 K were almost the same as the (010) single crystal surface. Photoluminescence intensities on the PLD films prepared at 1273 K were significantly intense and exceeded that on the CdWO4 (010) single crystal surface. (C) 2003 Elsevier B.V. All rights reserved.
    Scientific journal, English
  • Pulsed laser ablation of silicon with low laser fluence in a low-pressure of ammonia ambient
    CK Choo; M Tohara; K Enomoto; K Tanaka
    APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 228, 1-4, 120-127, Apr. 2004, Peer-reviwed, Silicon was ablated by 532 nm wavelength of Nd:YAG laser in ammonia gas ambient. The influence of laser fluence and gas ambient pressures between 1.33 x 10(1) to 1.33 x 10(-5) Pa on the deposited compound was studied by in situ X-ray photoelectron spectroscopy and transmission Fourier transform infrared spectroscopy techniques. The results indicate that the deposited compound is composed of nonstoichiometric silicon nitride (SiNx, x = 0-0.84). It has been shown that the composition of nitro-en to silicon is sensitive to the laser fluence; it increases with decreasing laser fluence. However, the ammonia gas ambient in these low pressures range had no influence on the composition of the deposited compound. The reaction of the ablated silicon with low-pressure ambient ammonia is proposed to be occurred on the substrate. (C) 2004 Elsevier B.V. All rights reserved.
    Scientific journal, English
  • Characterization and preparation of chained Si species in zeolite supercages
    K Tanaka; CK Choo; Y Komatsu; K Hamaguchi; M Yamaki; T Itoh; T Nishigaya; R Nakata; K Morimoto
    JOURNAL OF PHYSICAL CHEMISTRY B, AMER CHEMICAL SOC, 108, 8, 2501-2508, Feb. 2004, Peer-reviwed, Chained Si species were synthesized in Y-type zeolite supercages by the reaction with phenylsilane (PhSiH(3)) at 423 K. The preparation process was studied with the infrared spectra, and the prepared Si species were characterized with X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectra, and ultraviolet absorption spectra. The initial sticking reaction of SiH(x) species to zeolite framework was studied with a temperature-programmed desorption experiment on the deuterium-exchanged zeolite using a quadrupole mass spectrometer. Benzene molecules composed selectively with d(1) species (C(6)H(5)D) were desorbed with hydrogen molecules at 360-380 K; concurrently, hydroxyl groups in supercages disappeared. These results imply that the initial grafting reaction of Si species to a HY-zeolite framework proceeds through the thermal reaction of PhSiH(3) with hydroxyl groups in supercages at 298 K to yield [O]-SiH(3) and benzene. The formed [O]-SiH(x) species were characterized with infrared spectra as a function of reaction temperature. The wavenumbers shift in Si-H species was explained by the thermal conversion of [O]-SiH(3) (2180 cm(-1)) to [O](2)-SiH(2) (2208 cm(-1)) and [O](3)-SiH (2270 cm(-1)). The reaction of PhSiH(3) molecules with hydroxyl groups in supercages at 423 K suggests the propagation of Si species finally to yield [O](2)-Si(x)H(y). The successive propagation reaction with PhSiH3 yielded Si species with Si 2p XPS signals at 101.4 and 102.3 eV, which could be assigned to polysilane families. The quantitative XPS analysis implied that polysilane families with about 30 Si atoms were produced in a zeolite super cage. The zeolite pressed between metal barrels showed intense PL spectra peaked at 340 (3.6 eV) and 460 nm (2.7 eV). The peak intensities diminished considerably with treatment with oxygen gas at 573 K for 48 h, which caused the selective enhancement of X-ray diffraction intensity at around 2theta = 6degrees, characteristic of a zeolite (111) face. These results induce that surface contaminants such as organic compounds can be removed by the oxygen treatment as well as the zeolite crystallinity is improved by the decrease of oxygen vacancies. Chained Si species in zeolite supercages showed intense PL spectra at around 4 eV. The Si species can be extracted in hexane at 298 K, and the extracted species also showed redshifted intense PL spectra peaked at 4.07 eV. The broad UV spectra due to the polysilane backbone structure was detected at 220-280 nm. It is concluded that polysilane families are formed in zeolite supercages and absorb excitation photon energy and relax to show PL characteristic to the Si backbone structure.
    Scientific journal, English
  • Time-resolved photoluminescence on samarium, nickel, and cesium ion doped scintillator CdWO4 (010) single crystal surfaces
    K Tanaka; S Suzuki; CK Choo
    JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 95, 3, 1287-1293, Feb. 2004, Peer-reviwed, Photoluminescence (PL), cathode luminescence (CL), and x-ray excited luminescence (XL) are studied on Sm-, Ni-, and Cs-doped CdWO4 (010) single crystal surfaces. Luminescence spectra are deconvoluted to three constituent species at 2.77, 2.48, and 2.18 eV. Their intensities of the ion-doped CdWO4 crystals are compared with the undoped crystals. CL and XL intensities on Sm- and Ni-doped single crystals are suppressed to be about 20-40% of the undoped crystal. However, the luminescence component at 2.18 eV is dominant on the Sm-ion doped CdWO4 crystal. The x-ray diffraction peak at (020) face shifts to lower 2theta value on the Sm-ion doped CdWO4 single crystal, indicating that the crystal structure of CdWO4 is disturbed by Sm ions and the distance between (020) faces is enlarged. The distortion of the crystal structure will be induced by the exchange of W6+ ions into Sm3+ ions with larger ion diameter. Time-resolved PL decay analyses are studied on the doped and undoped crystals under excitation below the band gap. While only the slow decay component is detected with a lifetime of 14 mus on the undoped CdWO4 crystal, the fast and the slow PL decay components are detected with a lifetime of 0.7 and 10 mus on the three emission species in the doped CdWO4 crystals, respectively. The Cs-doped CdWO4 crystal has almost the same intensities for PL, CL, and XL as the undoped crystal. (C) 2004 American Institute of Physics.
    Scientific journal, English
  • Time-resolved photoluminescence on ion doped CdWO4 thin films prepared with pulsed laser deposition
    K Tanaka; S Suzuki; CK Choo
    JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 95, 3, 1294-1300, Feb. 2004, Peer-reviwed, Samarium-, nickel-, cesium-ion-doped and -undoped CdWO4 thin films are prepared by pulsed laser deposition (PLD) method. Photoluminescence (PL), cathode luminescence (CL), and x-ray excited luminescence (XL) are studied on these thin films. Luminescence spectra are deconvoluted to three luminescence species typically at 2.77, 2.48, and 2.18 eV. Luminescence intensities and the relative contribution of three deconvoluted components are compared with those on the undoped CdWO4 (010) single crystal surface. PL intensity on the undoped thin film can be compared to that on the (010) single crystal surface. Not only CL and XL intensities but also PL intensity drops drastically on ion-doped CdWO4 thin films. However, the emission component at about 2.2 eV is dominant and the relative contribution of 2.77 eV is diminished on the ion-doped PLD thin films. The x-ray diffraction data indicates that the (002) plane is most intense on these films and the peak shifts to lower 2theta value on the ion-doped CdWO4 thin films. These results imply that these films are polycrystalline and the interplane distance is enlarged on the ion-doped CdWO4 thin films. The stress of the crystal structure is associated with the origin of the PL component at about 2.2 eV which has been assigned to oxygen vacancies such as [WO5](4-) moieties in the crystal. Time-resolved PL decay analyses are studied on the PLD thin films at three wavelengths, 440 nm (2.82 eV), 550 nm (2.25 eV), and 650 nm (1.91 eV). The slow and fast decay component can be detected on the PLD thin films with a decay lifetime of 8-10 and 0.6-0.8 mus, respectively. Comparing to the corresponding CdWO4 (010) single crystal surfaces, the decay time of the slow PL component is decreased on PLD thin films. The PL component with fast decay time will be associated with the strain of CdWO4 crystal structure. (C) 2004 American Institute of Physics.
    Scientific journal, English
  • Size selective filtration of silicon nano-structures using AFI AlPO4-5 zeolite pores
    CK Choo; K Enomoto; K Tanaka
    MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY, ELSEVIER SCIENCE SA, 104, 1-2, 73-79, Nov. 2003, Peer-reviwed, The ablation of Si has been carried out in the presence of ammonia ambient. Non-stoichiometric (silicon rich) silicon nitride composed of Si-Si, NHx (x = 1.2) and SiHy (y = 1-3) are formed. Photoluminescence at visible region based on these nano-structures was observed at room temperature. AlPO4-5 zeolite was used as substrate. It is shown that zeolite can selectively control the size of the Si nano-structure and the emission wavelength as well, and that the deposited Si-N nano-structures can be migrated into the AlPO4-5 pores by annealing treatment. The photoluminescence red-shifted after annealing suggests that, the Si nano-crystals luminescence is ruled in the luminescence center. A theoretical model is proposed to explain the PL peak shift of the silicon nano-structures. (C) 2003 Elsevier B.V. All rights reserved.
    Scientific journal, English
  • Pulsed laser ultrahigh vacuum deposited silicon in the presence of excess cesium and oxygen studied with x-ray photoelectron spectroscopy and atomic force microscopy
    CK Choo; K Tanaka; H Suzuki; N Saotome; K Ichida
    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A, A V S AMER INST PHYSICS, 21, 4, 874-880, Jul. 2003, Peer-reviwed, Si/Cs/O clusters were prepared in an ultrahigh vacuum system with pulsed laser ablation of Si in the presence of Cs vapor and molecular oxygen. The effects of an O-2 ambient, the pressure, and the deposition sequence of Cs and O-2 on the oxidation state of cesium oxides and silicon oxides, as well as on the formation. of Si/Cs/O clusters, were studied with x-ray photoelectron spectroscopy and atomic force microscopy (AFM). Oxygen 1s spectra were deconvoluted to cesium oxide(s) at around 530.5 eV and silicon oxide(s) at 532.3 eV. From the low. binding energy side to the high binding energy, side, Si 2p spectra were assigned to negatively charged Si clusters (94 and 96 eV), silicon suboxide (102 eV), SiO2 (104 eV), and Si/Cs/O clusters (106 eV), respectively. The high binding energy: species was explained by the formation of Si(CsO1+x)(n) clusters. Surface, morphologies were influenced by the oxidation state of cesium oxides and their amount. The work function decrease as much as 0.5+/-0.1 eV was measured with ex situ AFM. (C) 2003 American Vacuum Society.
    Scientific journal, English
  • C-60/zeolite semiconductor electrode and the gas sensing
    K Tanaka; CK Choo; S Sumi; Y Kamitani; T Fujii; K Satoh; K Fukuda; R Nakata; M Yoshimune; Y Yoshinaga; T Okuhara
    JOURNAL OF PHYSICAL CHEMISTRY B, AMER CHEMICAL SOC, 106, 16, 4155-4161, Apr. 2002, Peer-reviwed, Sodium Y type zeolite synthesized with homogeneous gels was deposited as thin films on tantalum toothcombs type electrode. C-60 molecules were deposited on the zeolite electrode surface by sublimation in a vacuum and were encapsulated in zeolite supercages by the thermal diffusion. The encapsulation was indicated by a decrease of the pore volume measured by argon gas adsorption. The potassium deposited K-Cb-60/zeolite electrode as well as zeolite and C-60/zeolite electrodes showed the behaviors characteristic to semiconductors in their measurements of currents in dark with temperature. The dependence of their dark currents on temperature was similar, which suggests that carrier formation through thermal band-gap excitation will be mainly caused by zeolite. The C-60/zeolite and K-C-60/zeolite electrodes showed rapid current responses repeatedly at 298 K under UV light irradiation. The introduction of oxygen gas to the C60/zeolite electrode under UV light irradiation resulted in both rapid and slow current decays with time. The current decreased and that remained in the rapid current decay were interpreted as contributions mainly from n-type (80%) and p-type character (20%), respectively. The slow current decay was interpreted by diffusion of oxygen into zeolite supercages. Ethylene sensing on the C-60/zeolite electrode was possible in dark and showed a pressure dependency of Langmuir type isotherm. The result implies that such sensing is caused by compressing ethylene molecules in zeolite supercages.
    Scientific journal, English
  • CaWO4 thin films synthesized by pulsed laser deposition
    K Tanaka; K Fukui; K Ohga; CK Choo
    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS, A V S AMER INST PHYSICS, 20, 2, 486-491, Mar. 2002, Peer-reviwed, Thin films of CaWO4 were synthesized by pulsed laser deposition (PLD) using targets composed of CaO and WO3 oxide mixtures. The crystallinity of CaWO4 thin films strongly depended on PLD conditions, that is, substrate temperature, ambient oxygen pressure, and laser fluence. Congruent thin films with stoichiometry were obtained at 873 K. They showed photoluminescence (PL) at room temperature. PL spectra were characteristic with excitation wavelength, peaked at 440 and 520 nm, which were excited with 340-360 and 300-330 nin, respectively. Cathodeluminescence (CL) spectra could be recorded at room temperature on the PLD thin films and were composed of the same species as observed in PL spectra. Intensity of CL spectra increased drastically after postannealing the PLD thin films at 873 K. PLD experiments were also carried out using CaWO4 targets at the same conditions. Crystalline CaWO4 thin films were obtained much easier than PLD using targets composed of CaO and WO3 oxide mixtures. (C) 2002 American Vacuum Society.
    Scientific journal, English
  • Design and construction of alkali metals evaporation unit for UHV systems
    C.K. Choo; 小越 一輝; 田中 勝己
    Bulletin of The University of Electro-Communications, The University of Electro-Communications, 14, 2, 177-181, 2002, Peer-reviwed
    Research institution, Japanese
  • Sm-doped CdWO4 thin films synthesized by pulsed laser deposition
    K Tanaka; K Ohga; CK Choo; R Nakata
    JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 90, 10, 5369-5375, Nov. 2001, Peer-reviwed, Samarium doped CdWO4 (Sm-CdWO4) thin films were synthesized by pulsed laser deposition (PLD) using pressed powder targets composed of Sm2O3, CdO, and WO3 mixtures. Congruent, stoichiometric, and crystalline thin films were obtained on glass substrates at 873 K using targets with 0.01 at. % Sm. The x-ray activated photoluminescence (x-ray PL) spectra were redshifted by about 40 nm at 298 K. Changes of the PL component at 2.85 eV into those at 2.20 and 2.52 eV were typical in their convolutions. These PL components showed very similar dependencies on excitation wavelengths, indicating that CdWO4 related PL emissions in the Sm-doped PLD films are relaxed from the same midband excited state. The PL peaks characteristic to Sm3+ had two sidebands shifted to both lower and higher energy sides as much as 0.03 eV. Plume emission spectra were analyzed to elucidate effects of Sm on our PLD processes. It was interpreted that energy transfer should occur between excited neutral Cd to the excited state of Sm3+ in laser plume. (C) 2001 American Institute of Physics.
    Scientific journal, English
  • Preparation and evaluation of nitrogen-terminated silicon nanoparticles: laser annealing effect
    CK Choo; T Sakamoto; M Tohara; K Tanaka; R Nakata; N Okuyama
    SURFACE SCIENCE, ELSEVIER SCIENCE BV, 445, 2-3, 480-487, Jan. 2000, Peer-reviwed, Nitrogen-terminated silicon nanoparticles were synthesized on AFI AlPO4-5 zeolite by pulsed laser ablation of silicon target in the presence of 1.33 x 10(-5) Pa of ammonia and were annealed by multiple laser shots at 532 nm. The samples were characterized by X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy and UV-vis absorption measurements. The results indicate that they are composed of nonstoichiometric silicon nitride nanoparticles as well as silicon species with dangling bonds. NHx (x = 1,2) polyhydride species are dissociated by pulsed laser annealing, which shows the improvement of the silicon and silicon nitride crystallinities. It is suggested that the nanoparticles will agglomerate as clusters after laser annealing. According to the Tauc plot obtained from UV-vis absorption data, a blue shift of band gap energy from bulk silicon was observed. (C) 2000 Elsevier Science B.V. All rights reserved.
    Scientific journal, English
  • Oxygen containing silicon clusters on Teflon and their work functions studied with X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy
    K Tanaka; T Sakamoto; M Tohara; CK Choo; R Nakata
    APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 148, 3-4, 215-222, Jul. 1999, Peer-reviwed, Silicon species were deposited on tetrafluoroethylene (Teflon) with pulsed laser silicon ablation at 532 nm under UHV. Surface species were studied with X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Tetrafluorocarbon (CF4) was easily desorbed by the decomposition reaction of Teflon with flying silicon species. Surface species were characterized as a function of pulsed laser shots. Silicon species were terminated with oxygen in gas phase to form two kinds of SiOx clusters (x < 0.3) in addition to oxygen terminated silicon networks. Their work functions could be estimated by the shift of their Fermi energies. (C) 1999 Elsevier Science B.V. All rights reserved.
    Scientific journal, English
  • Characterization of nitrogen terminated silicon nanoparticles on AFI zeolite with X-ray and ultraviolet photoelectron spectroscopies
    CK Choo; T Sakamoto; K Tanaka; R Nakata
    APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 148, 1-2, 116-125, Jun. 1999, Peer-reviwed, Nitrogen terminated silicon nanoparticles were synthesized on AFI AlPO4-5 zeolite by pulsed Laser ablation of silicon target in the presence of 1.33 x 10(-5) Pa of ammonia, and were characterized in situ by X-ray photoemission spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Nonstoichiometric silicon nitride and unterminated silicon nanoparticles with size of estimated to be similar to 5.4 Angstrom in diameter were existed. They were found to migrate and diffuse into the AlPO4-5 channels at 373 K and migrate back to the external surface at 503 K. The effect of sample annealing was studied at 373 K. Thr change of silicon surface state (unterminated silicon nanoparticles) to hydride species was observed concurrently with breaking of the NHx species. This result implies that the NHx species remained on the silicon particles form Si3N4 like bonds and the dissociated H-species are bound to the unterminated silicon surface. (C) 1999 Elsevier Science B.V. All rights reserved.
    Scientific journal, English
  • Negatively charged subnanometer-sized silicon clusters and their reversible migration into AFI zeolite pores studied with X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy
    C Choo; T Sakamoto; K Tanaka; R Nakata; T Asakawa
    APPLIED SURFACE SCIENCE, ELSEVIER SCIENCE BV, 140, 1-2, 126-137, Feb. 1999, Peer-reviwed, Subnanometer sized silicon clusters were deposited on AR zeolite (AlPO4-5: one-dimensional channel diameter < 0.73 nm) by pulsed laser ablation of silicon wafer. Their electronic structures were elucidated in situ by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Core level Si 2p spectra were analyzed into five components, Si(I) to Si(V). Si(I) and Si(II) species selectively increased with a constant ratio during pulsed laser silicon ablation. Their binding energies (BEs) were below 99.5 eV implying negatively charged states. Charge transfer occurred between silicon clusters and framework oxygen and phosphor ions. It was interpreted that the stability of negative charge is due to large electron affinity of silicon clusters, The intensity of XPS signals decreased as a function of time and at the same time the channels were blocked. These results were interpreted due to migration of silicon clusters into zeolite pores. The estimated activation energy (57 kJ/mol) suggests that rate-determining step of the migration is reflected by a weak adsorbed state of silicon clusters similar to physisorbed state. The silicon clusters were partially oxidized at 573 K, which was interpreted as a driving force of backward migration from zeolite pores to the external surface. The composition of silicon cluster was discussed based on homogeneous dispersion of single species. (C) 1999 Elsevier Science B.V. All rights reserved.
    Scientific journal, English

Lectures, oral presentations, etc.

  • NOプローブ分子を用いた光電子分光法(XPS,UPS)によるN-doped a-C薄膜の表面構造の評価
    村田悠馬; 中山廉平; 小野洋; チュウチャオキョン; 田中勝己
    Oral presentation, Japanese, 第77回応用物理学会秋季学術講演会, Domestic conference
    16 Sep. 2016
  • Characterization and Photocatalytic Activities of SrTi1-xCoxO3 Thin Films Prepared by Liquid State Pulsed Laser Ablation II
    Fumihiko Ichihara; Murata Yuma; Hiroshi Ono; Cheow-Keong Choo; Katsumi Tanaka
    Oral presentation, Japanese, 第63回応用物理学会春季学術講演会, Domestic conference
    20 Mar. 2016
  • 光電子分光法を用いたN-doped a-C薄膜の電荷状態の解析
    Murata Yuma; Fumihiko Ichihara; Hiroshi Ono; Cheow-Keong Choo; Katsumi Tanaka
    Oral presentation, Japanese, 第63回応用物理学会春季学術講演会, Domestic conference
    20 Mar. 2016
  • Characterization and Photocatalytic Activities of SrTi1-xCoxO3 Thin Films Prepared by Liquid State Pulsed Laser Ablation
    Fumihiko Ichihara; Murata Yuma; Hiroshi Ono; Cheow-Keong Choo; Katsumi Tanaka
    Oral presentation, Japanese, 第76回応用物理学会秋季学術講演会, Domestic conference
    16 Sep. 2015
  • 13C,1H固体NMRを用いたN-doped DLC薄膜の構造解析
    村田悠馬; Choo Cheow-keong; 小野洋; 桑原大輔; 田中勝己
    Oral presentation, Japanese, 第75回応用物理学会秋季学術講演会
    19 Sep. 2014
  • CoドープSrTiO3の可視光下での光触媒活性
    市原文彦; 小野 洋; Choo Cheow-Keong; 田中勝己
    Oral presentation, Japanese, 第75回応用物理学会秋季学術講演会
    18 Sep. 2014
  • Characterization of N-doped DLC Thin Films using Photoelectron Spectroscopy
    Y.Murata; I. Fumihiko; H.Ono; C-K Choo; K.Daisuke; K.Tanaka
    Oral presentation, Japanese, 第76回応用物理学会秋季学術講演会
    15 Sep. 2014
  • Characterization of N-doped DLC thin films prepared by hydrocarbons pyrolysis method
    Y. Murata; C-K. Choo; H. Ono; Y. Nagai; K. Tanaka
    Oral presentation, English, International Conference on Diamond and Carbon Materials, International conference
    10 Sep. 2014
  • Characterization of N-doped DLC thin films prepared by the thermal decomposition method
    Y. Murata; O.Hiroshi; Cheow-Keong Choo; Y. Nagai; K. Tanaka
    Oral presentation, Japanese, 第 74 回応用物理学会秋季学術講演会
    18 Sep. 2013
  • 音叉型水晶振動子による単結晶グラファイト基板上4Heのスリップ現象の観測(IV)
    岡村衡; 野田啓; 谷口淳子; C.K.Choo; 鈴木勝
    Oral presentation, Japanese, 日本物理学会,第68回年次大会, Domestic conference
    29 Mar. 2013
  • Preparation and characterization of SrTiO_3_ nano particles by liquid phase laser ablation
    Kyo Cyou; Choo Cheow-Keong; Yutaka Nagai; Katumi Tanaka
    Oral presentation, Japanese, 第73回応用物理学会学術講演会,第73回応用物理学会学術講演会
    Sep. 2012
  • Properties of Si nano-crystals prepared by liquid-phase PLA method
    K. Funahara; Choo Cheow-Keong; Yutaka Nagai; Katumi Tanaka
    Oral presentation, Japanese, 第73回応用物理学会学術講演会,第73回応用物理学会学術講演会
    Sep. 2012
  • Bismuth doped CaWO_4_ thin films prepared by Pulse Laser Ablation in O_2_
    Yoshihiro Ito; Choo Cheow-Keong; Yutaka Nagai; Katumi Tanaka
    Oral presentation, Japanese, 第73回応用物理学会学術講演会,第73回応用物理学会学術講演会
    Sep. 2012
  • Diamond Like carbon thin films prepared by the thermal decomposition of methane using a catalyst
    Yasutaka Nishinaga; Choo Cheow-Keong; Yutaka Nagai; Katumi Tanaka
    Oral presentation, Japanese, 第73回応用物理学会学術講演会,第73回応用物理学会学術講演会
    Sep. 2012
  • Synthesis of TiO2 nano-particles by PLA of TiN target.
    Ohtaka Masashi; C.K.Choo; Yutaka Nagai; Katsumi Tanaka
    Oral presentation, Japanese, Extended Abstracts (The 59rd Meeting, 2012); The Japan Society of Applied Physics
    Mar. 2012
  • 強靭耐摩耗用DLC膜
    C.K. Choo; 田中 勝己
    Invited oral presentation, Japanese, 三遠南信クラスター推進会議, 三遠南信クラスター推進会議、浜松商工会議所、はままつ産業創造センター、(独)科学技術振興機構JSTイノベーションサテライト茨城・静岡
    Jan. 2012
  • Characterization and photocatalytic activity of oxygen-defective CaWO_4_
    Atsushi Ohta; C.K.Choo; Yutaka Nagai; Katsumi Tanaka
    Oral presentation, Japanese, Extended Abstracts (The 71rd Autumn Meeting, 2010); The Japan Society of Applied Physics
    Sep. 2010
  • Photocatalytic Activity of TiO_2_ nano-particles prepared by liquid phase laser ablation
    Yasuhiro Tomatsu; C.K.Choo; Yutaka Nagai; Katsumi Tanaka
    Oral presentation, Japanese, Extended Abstracts (The 71rd Autumn Meeting, 2010); The Japan Society of Applied Physics
    Sep. 2010
  • Evaluation and Photo-catalytic Activity of Bi Based Mixed Oxides
    Kenji Tomizu; Yutaka Nagai; C.K. Choo; Katsumi Tanaka
    Oral presentation, Japanese, Extended Abstracts (The 71rd Autumn Meeting, 2010); The Japan Society of Applied Physics
    Sep. 2010
  • Evaluation of Si nano particles prepared by annealing at ultrahigh vacuum
    袁 群; Cheow-Keong Choo; 永井 豊; 田中勝己
    Oral presentation, Japanese, 第70回応用物理学会学術講演会
    Sep. 2009
  • Micro Raman analysis of the DLC film prepared by hydrocarbon pyrolysis
    古川 徹; Cheow-Keong Choo; 永井 豊; 田中勝己
    Oral presentation, Japanese, 第70回応用物理学会学術講演会
    Sep. 2009
  • 水中レーザーアブレーションで作製したチタニア微粒子によるメチレンブルー光分解反応
    高尾 誠; チュウ チャオキョン; 田中 勝己
    Oral presentation, Japanese, 第25回表面科学講演大会,第25回表面科学講演大会
    Sep. 2006
  • 不純物ドープを目指した酸化チタンの作製とその物性評価
    田辺明良; 田中勝己; C.K.Choo
    Oral presentation, Japanese, 第94回触媒討論会
    2004
  • 水中PLD法によるTiO_2_ナノ微粒子の作製と評価
    岩淵 明; C.K. Choo; 田中 勝己
    Oral presentation, Japanese, 第94回触媒討論会
    2004
  • ゼオライトケージ内Si微粒子の特性
    佐藤 聖子; 桑原 大介; C.K. Choo; 田中 勝己
    Oral presentation, Japanese, 第65回応用物理学術講演会
    2004
  • レーザーアブレーション法により作製した K/O/Si 表面化合物の評価
    須澤 大輔; C.K. Choo; 田中 勝己
    Oral presentation, Japanese, 第65回応用物理学術講演会
    2004
  • レーザーアブレーション法を用いた不純物ドープダングステン酸化膜の作製と評価
    吉井 貴志; C.K. choo; 田中 勝己
    Oral presentation, Japanese, 第64回応用物理学会学術講演会
    Aug. 2003
  • 水溶液中のレーザーアブレーションで作製したTiO_2_微粒子の物性評価 : その3
    岩渕 明; 田辺 明良; 清田 智子; 難波 健介; C.K. Choo; 田中 勝己
    Oral presentation, Japanese, 第64回応用物理学会学術講演会
    Aug. 2003
  • レーザーアブレーションによるSi/K/O表面化合物の形成に関する評価
    田中 貴臣; 須沢 大輔; C.K. Choo; 田中 勝己
    Oral presentation, Japanese, 第64回応用物理学会学術講演会
    Aug. 2003
  • Luminescence wavelength controll of CdWO_4_ thin films
    田中 勝己; 鈴木 聡史; C.K. Choo
    Oral presentation, Japanese, 日本化学会第83春季年会
    Mar. 2003
  • 水溶液中のレーザーアブレーションで作製したTiO_2_微粒子の物性評価 : その2
    岩渕 明; 田辺 明良; 清田 智子; 難波 健介; C.K. Choo; 田中 勝己
    Oral presentation, Japanese, 第50回応用物理学関係連合講演会
    Mar. 2003
  • レーザーアブレーションによるKO_2_からの脱離種に関する評価
    田中 貴臣; 須澤 大輔; C.K. Choo; 田中 勝己
    Oral presentation, Japanese, 第50回応用物理学関係連合講演会
    Mar. 2003
  • Evaluation of Titanium dioxide particles produced by laser ablation in aqua solution.
    岩渕 明; C.K. Choo; 田中 勝己
    Oral presentation, Japanese, Extended Abstracts (The 63rd Autumn Meeting, 2002); The Japan Society of Applied Physics
    Sep. 2002
  • Synthsis and evalution of Cs doped CdWO4 by pulsed laser deposition.
    吉井 貴志; 鈴木 聡史; C.K. choo; 田中 勝己
    Oral presentation, Japanese, Extended Abstracts (The 63rd Autumn Meeting, 2002); The Japan Society of Applied Physics
    Sep. 2002
  • Stability of Cesium-Oxide on Teflon
    小越 一輝; C.K. Choo; 田中 勝己
    Oral presentation, Japanese, Extended Abstracts (The 63rd Autumn Meeting, 2002); The Japan Society of Applied Physics
    Sep. 2002
  • アンモニアで終端シリコン微粒子の評価
    榎本和弘; 小越一輝; 戸原誠人; C.K. Choo; 田中勝己
    Oral presentation, Japanese, 第49回応用物理学関係連合講演会
    Mar. 2002
  • A study of Cesium-Oxide on Teflon
    小越一輝; C.K. Choo; 田中勝己
    Oral presentation, Japanese, 第49回応用物理学関係連合講演会
    Mar. 2002
  • レーザーアブレーション法で作成した窒素終端シリコン微粒子の評価
    榎本和弘; 小越一輝; 戸原誠人; C.K. Choo; 田中勝己
    Oral presentation, Japanese, 第62回応用物理学会学術講演会
    Sep. 2001
  • ゼオライト細孔内へのSi微細構造の作製と発光特性
    小松友子; 浜口宏治; 山来雅弘; 伊東知仁; C.K. Choo; 田中勝己
    Oral presentation, Japanese, 第62回応用物理学会学術講演会
    Sep. 2001
  • MO_x_/CdO/WO_3_ 系ターゲットからのプルーム発光スペクトル解析(M = 希土類など)
    鈴木聡史; 大賀功一; C.K. Choo; 田中勝己
    Oral presentation, Japanese, 第62回応用物理学会学術講演会
    Sep. 2001
  • レーザーアブレーション法によるCd_1-x_Sm_x_WO_4_の薄膜の作成と発光特性
    大賀功一; C. K. Choo; 田中勝己
    Oral presentation, Japanese, 第61回応用物理学会学術講演会
    Sep. 2000
  • C_60_/NaYゼオライトのガス応答特性
    鷲見聖二; 神谷美行; C. K. Choo; 田中勝己
    Oral presentation, Japanese, 第61回応用物理学会学術講演会
    Sep. 2000
  • ゼオライト内へのシリコン種の作成プロセスとその発光特性
    濱口宏治; 山来雅弘; 伊東知仁; C. K. Choo; 田中勝己
    Oral presentation, Japanese, 第61回応用物理学会学術講演会
    Sep. 2000
  • 光電子分光法を用いた窒素終端シリコン微粒子の状態分析
    戸原 誠; チュウ チャオキョン; 佐藤 千嘉夫; 田中 勝己
    Oral presentation, Japanese, 第60回応用物理学会学術講演会
    Sep. 1999
  • 窒素終端Si微粒子の作成と評価:レーザーアニーリング効果
    チュウ チャオキョン; 坂本 隆; 田中 勝己; 中田 良平
    Oral presentation, Japanese, 第46回応用物理学関係連合講演会
    Mar. 1999
  • シリコン及び窒素終端シリコン微粒子のテフロン上への作製とその評価
    坂本 隆; 戸原 誠; チュウ チャオキョン; 田中 勝己
    Oral presentation, Japanese, 第59回応用物理学会学術講演会
    Sep. 1998
  • アンモニアを用いた窒素終端Si超微粒子の作成と評価
    チュウ チャオキョン; 坂本 隆; 田中 勝己; 中田 良平
    Oral presentation, Japanese, 第45回応用物理学関係連合講演会
    Mar. 1998
  • ゼオライトAlPO_4_-5を用いたSi超微粒子の作成と評価
    チュウ チャオキョン; 田中 勝己; 中田 良平
    Oral presentation, Japanese, 第57回応用物理学会学術講演会
    Sep. 1997

Courses

  • Science and Technology in Japan A
    Apr. 2019 - Present
    The University of Electro-Communications, Undergraduate liberal arts, Japan
  • Environmental Engineering
    Apr. 2017 - Present
    The University of Electro-Communications, 基盤理工(III類), Undergraduate special subjects, Japan
  • Graduate Overseas Language Training II
    Apr. 2017 - Present
    The University of Electro-Communications, 英語で開講する科目, Graduate school liberal arts course, Japan
  • Graduate Overseas Language Training Ⅰ
    Apr. 2017 - Present
    The University of Electro-Communications, 英語で開講する科目, Graduate school liberal arts course, Japan
  • UEC Academic Skills II (Information Literacy and Research) Spring semester
    Apr. 2014 - Present
    The University of Electro-Communications, 英語で開講する国際科目、西東京三大学連携科目, Undergraduate liberal arts, Japan
  • UEC Academic Skills II (Information Literacy and Research) Fall semester
    Apr. 2014 - Present
    The University of Electro-Communications, 英語で開講する国際科目、西東京三大学連携科目, Undergraduate liberal arts, Japan
  • UEC Academic Skills III (Publishing Literacy and Research) Spring semester
    Apr. 2014 - Present
    The University of Electro-Communications, 英語で開講する国際科目、西東京三大学連携科目, Undergraduate liberal arts, Japan
  • UEC Academic Skills III (Publishing Literacy and Research) Fall semester
    Apr. 2014 - Present
    The University of Electro-Communications, 英語で開講する国際科目、西東京三大学連携科目, Undergraduate liberal arts, Japan
  • UEC Academic Skills I (Computer Literacy) Fall semester
    Apr. 2014 - Present
    The University of Electro-Communications, 英語で開講する国際科目、西東京三大学連携科目, Undergraduate liberal arts, Japan
  • UEC Academic Skills I (Computer Literacy) Fall semester
    Apr. 2014 - Present
    The University of Electro-Communications, 英語で開講する国際科目、西東京三大学連携科目, Undergraduate liberal arts, Japan

Affiliated academic society

  • シリコンテクノロジー分科会
  • 応用物理学会

Research Themes

  • 常圧炭化水素熱分解による金属上の機能性炭素材料作製と評価
    田中 勝己
    メタンとアルゴンの混合ガスを1気圧下で金属基板上に800~1100℃で反応させDLC薄膜を作製した。金属基板として、純度99.5%と99.99%の2種類の鉄と鋼材SCM440を用いた。表面生成物を顕微ラマン分光法、硬度測定、SEMによる膜厚測定から評価した。800℃で硬度900以上、膜厚3~6μmのDLC膜の合成に成功した。純度の低い鉄基板の場合、バルク中の酸素原子が表面に拡散し酸化鉄を生成する場合のある事が分かった。条件を変えることで純度の低い鉄基板の場合においてもDLC膜の合成が可能であった。DLC膜と金属基板の結合を強固にする界面層の構造についてラマン測定から解明する事を試みた。
    01 Apr. 2012 - 31 Mar. 2015
  • 触媒反応解析
    (株)キャンパスクリエイト
    2013 - 2014
  • 薄膜分析のFTIRによる分析と評価
    C.K. Choo
    日野自動車株式会社, Principal investigator, Research commissioned by a company
    2012 - 2012

Industrial Property Rights

  • METAL WITH DIAMOND-LIKE CARBON FILM, AND METHOD FOR FORMING DIAMOND-LIKE CARBON FILM
    Patent right, TANAKA, KATSUMI, CHOO, CHEOW KEONG, PCT/JP2012/065527, Date applied: 18 Jun. 2012, THE UNIVERSITY OF ELECTRO-COMMUNICATIONS, TANAKA, KATSUMI, CHOO, CHEOW KEONG, WO2013/011784, Date announced: 24 Jan. 2013, US2014/0193594A11, Date published: 10 Jul. 2014, EP2735624, Date issued: 01 Aug. 2018
  • ダイヤモンドライクカーボン膜の形成方法
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