Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 103

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Enhancement of SiO$$_{2}$$/Si(001) interfacial oxidation induced by thermal strain during rapid thermal oxidation

Ogawa, Shuichi*; Tang, J.*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Takakuwa, Yuji*

Journal of Chemical Physics, 145(11), p.114701_1 - 114701_7, 2016/09

 Times Cited Count:3 Percentile:14.34(Chemistry, Physical)

Enhancement of SiO$$_{2}$$/Si(001) interfacial oxidation induced by thermal strain during rapid thermal oxidation was revealed by real time photoelectron spectroscopy using high intensity and high energy-resolution synchrotron radiation. This experimental result indicates the usefulness of the unified Si oxidation reaction model mediated by point defect generation.

Journal Articles

Valence-band electronic structure evolution of graphene oxide upon thermal annealing for optoelectronics

Yamaguchi, Hisato*; Ogawa, Shuichi*; Watanabe, Daiki*; Hozumi, Hideaki*; Gao, Y.*; Eda, Goki*; Mattevi, C.*; Fujita, Takeshi*; Yoshigoe, Akitaka; Ishizuka, Shinji*; et al.

Physica Status Solidi (A), 213(9), p.2380 - 2386, 2016/09

 Times Cited Count:8 Percentile:46.1(Materials Science, Multidisciplinary)

We report valence-band electronic structure evolution of graphene oxide (GO) upon its thermal reduction. The degree of oxygen functionalization was controlled by annealing temperature, and an electronic structure evolution was monitored using real-time ultraviolet photoelectron spectroscopy. We observed a drastic increase in the density of states around the Fermi level upon thermal annealing at $$sim$$ 600$$^{circ}$$C. The result indicates that while there is an apparent bandgap for GO prior to a thermal reduction, the gap closes after an annealing around that temperature. This trend of bandgap closure was correlated with the electrical, chemical, and structural properties to determine a set of GO material properties that is optimal for optoelectronics. The results revealed that annealing at a temperature of 500$$^{circ}$$C leads to the desired properties, demonstrated by a uniform and an order of magnitude enhanced photocurrent map of an individual GO sheet compared to an as-synthesized counterpart.

Journal Articles

Self-accelerating oxidation on Si(111)7$$times$$7 surfaces studied by real-time photoelectron spectroscopy

Tang, J.*; Nishimoto, Kiwamu*; Ogawa, Shuichi*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Watanabe, Daiki*; Teraoka, Yuden; Takakuwa, Yuji*

Surface and Interface Analysis, 46(12-13), p.1147 - 1150, 2014/12

 Times Cited Count:1 Percentile:2.1(Chemistry, Physical)

Journal Articles

Graphene growth and carbon diffusion process during vacuum heating on Cu(111)/Al$$_{2}$$O$$_{3}$$ substrates

Ogawa, Shuichi*; Yamada, Takatoshi*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Hasegawa, Masataka*; Teraoka, Yuden; Takakuwa, Yuji*

Japanese Journal of Applied Physics, 52(11), p.110122_1 - 110122_8, 2013/11

 Times Cited Count:17 Percentile:63.5(Physics, Applied)

Journal Articles

Relation between oxidation rate and oxidation-induced strain at SiO$$_{2}$$/Si(001) interfaces during thermal oxidation

Ogawa, Shuichi*; Tang, J.*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Teraoka, Yuden; Takakuwa, Yuji*

Japanese Journal of Applied Physics, 52(11), p.110128_1 - 110128_7, 2013/11

 Times Cited Count:10 Percentile:46(Physics, Applied)

Journal Articles

SiO desorption kinetics of Si(111) surface oxidation studied by real-time photoelectron spectroscopy

Tang, J.*; Nishimoto, Kiwamu*; Ogawa, Shuichi*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Watanabe, Daiki*; Teraoka, Yuden; Takakuwa, Yuji*

e-Journal of Surface Science and Nanotechnology (Internet), 11, p.116 - 121, 2013/11

Journal Articles

Rehearsal and actual measurement of Fugen spent fuel assemblies by integrated PNAR and SINRD under the JAEA-USDOE collaboration program

Hayashi, Kenta; Nakamura, Takahisa; Takagi, Hisatsugu; Horie, Kaoru; Nakayama, Tamotsu; Hashimoto, Kazuhiko; Hayashi, Shoichi; Nakamura, Shinji; Takenaka, Shigeki; Ishizuka, Nobuo; et al.

Proceedings of INMM 54th Annual Meeting (CD-ROM), 10 Pages, 2013/07

JAEA and USDOE (Los Alamos National Laboratory (LANL)) have been collaborating on spent fuel measurements with a PNAR/SINRD NDA instrument at Fugen, in the course of the NGSI Spent Fuel Nondestructive Assay Project. In this collaboration, LANL's role has been to design and fabricate the detector (integrated PNAR and SINRD system), while JAEA's role has been to undertake the installation of the detector at the appropriate position in the spent fuel pool and to prepare for the actual measurements. In this paper we report the rehearsal of the measurement using a mock-up detector and a dummy fuel assembly in December 2012 and the plan of actual measurements in June 2013 (at the time of submission of this paper).

Journal Articles

Nonlinear O$$_{2}$$ pressure dependence of the initial oxide growth kinetics on Si(111) surfaces; Photoelectron spectroscopy observation and molecular orbital calculation of oxidation states

Tang, J.*; Nishimoto, Kiwamu*; Ogawa, Shuichi*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Watanabe, Daiki*; Teraoka, Yuden; Takakuwa, Yuji*

Dai-18-Kai Getosutakku KenkyuKai Yokoshu, p.191 - 194, 2013/01

Journal Articles

Vacuum annealing formation of graphene on diamond C(111) surfaces studied by real-time photoelectron spectroscopy

Ogawa, Shuichi*; Yamada, Takatoshi*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Hasegawa, Masataka*; Teraoka, Yuden; Takakuwa, Yuji*

Japanese Journal of Applied Physics, 51(11), p.11PF02_1 - 11PF02_7, 2012/11

 Times Cited Count:23 Percentile:70.04(Physics, Applied)

Journal Articles

Observation of graphene-on-diamond formation studied by real-time photoelectron spectroscopy

Ogawa, Shuichi*; Yamada, Takatoshi*; Ishizuka, Shinji*; Watanabe, Daiki*; Yoshigoe, Akitaka; Hasegawa, Masataka*; Teraoka, Yuden; Takakuwa, Yuji*

Hyomen Kagaku, 33(8), p.449 - 454, 2012/08

Graphene-on-insulator structures are required for fabrication of the graphene transistor. Diamond has been attracted as the substrate for graphene growth because it has a larger band gap and break down voltage compared with SiC. The detail of graphitization on a diamond surface has not been clarified yet because the nondestructive evaluation for graphene-on-diamond (GOD) structure was hard. In this study, we have developed an evaluation method of GOD based on the photoemission spectroscopy using synchrotron radiation focusing the shift of photoelectron spectra due to band bending. We can clearly determine the graphitization temperature on the diamond C(111) surface as approximately 1120 K, which is lower than that on an SiC substrate. It is also confirmed from C 1s photoelectron spectra, there is the buffer layer at the interface between the grapheme layer and the diamond substrate.

Journal Articles

Oxidation-enhanced condensation of Ge atoms on Si$$_{1-x}$$Ge$$_{x}$$ alloy layer studied by real-time photoelectron spectroscopy

Ogawa, Shuichi*; Hozumi, Hideaki*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Kaga, Toshiteru*; Teraoka, Yuden; Takakuwa, Yuji*

Oyo Butsuri Gakkai Hakumaku, Hyomen Butsuri Bunkakai, Shirikon Tekunoroji Bunkakai Kyosai Tokubetsu Kenkyukai Kenkyu Hokoku, p.67 - 70, 2011/01

The oxidation-enhanced Ge atoms condensation kinetics on an Si$$_{1-x}$$Ge$$_{x}$$ alloy layer has been investigated by the real-time photoemission spectroscopy using the synchrotron radiation. The Si$$_{1-x}$$Ge$$_{x}$$ alloy layer was formed with a thermal evaporation method on a p-type Si(001) surface, and this alloy layer was oxidized at Langmuir-type adsorption. During oxidation at 773 KC, it is found that the Ge atoms are not oxidized, only SiO$$_{2}$$ film is formed on the Si$$_{1-x}$$Ge$$_{x}$$ alloy layer. Furthermore, the desorption of GeO molecules does not occur during the oxidation of alloy layer. On the other hand, not only Si atoms but also Ge atoms are oxidized at room temperature. This difference can be explained using the unified oxidation model mediated by the point defect generation, namely it is suggested that a lot of vacancies are generated during oxidation of the Si$$_{1-x}$$Ge$$_{x}$$ alloy layer at 773K and Ge atoms diffuse through these vacancies.

Journal Articles

Oxidation-enhanced difusion of C atoms on Si$$_{1-x}$$C$$_{x}$$ alloy layer/Si(001) surface under oxide growth and etching conditions

Hozumi, Hideaki*; Ogawa, Shuichi*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Harries, J.; Teraoka, Yuden; Takakuwa, Yuji*

Oyo Butsuri Gakkai Hakumaku, Hyomen Butsuri Bunkakai, Shirikon Tekunoroji Bunkakai Kyosai Tokubetsu Kenkyukai Kenkyu Hokoku, p.181 - 184, 2010/01

The oxidation kinetics on the Si$$_{1-x}$$C$$_{x}$$ alloy layer has been investigated using the real-time XPS measurement. Experiments were performed at the BL23SU of SPring-8. The Si$$_{1-x}$$C$$_{x}$$ alloy layer was formed with exposing a p-type Si(001) surface to ethylene, and the Si$$_{1-x}$$C$$_{x}$$ alloy layer was oxidized at Langmuir-type adsorption (773 K) and 2D oxide island growth (933 K), respectively. In case of Langmuir-type adsorption, it is found that no carbon atoms are oxidized and carbon concentration at the SiO$$_{2}$$/Si interface increases. These results indicate the carbon atom condensation occurs, leading to the SiO$$_{2}$$/Si$$_{1-x}$$C$$_{x}$$/Si layers formation. On the other hand, the carbon concentration decrease by 20% in spite of the etching of 38 Si layers in the 2D oxide island growth. Based on these results, it is found that the diffusion of carbon atoms is occurred due to not only oxide growth but also Si etching.

Journal Articles

Real-time photoelectron spectroscopy study of 3C-SiC nucleation and growth on Si(001) surface by carbonization with ethylene

Hozumi, Hideaki*; Ogawa, Shuichi*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Harries, J.; Teraoka, Yuden; Takakuwa, Yuji*

JSPS 141 Committee Activity Report, p.317 - 322, 2009/12

It is reported that Si$$_{1-x}$$C$$_{x}$$ alloy layer was formed on an Si(001) surface with C$$_{2}$$H$$_{4}$$ exposure at 933 K before nucleation. However information of the chemical bonding state and concentration of adsorbed carbon has not been clear. Therefore the carbonization reaction kinetics on an Si(001) surface reacted with C$$_{2}$$H$$_{4}$$ exposure was observed by real-time XPS to investigate the 3C-SiC nucleation kinetics. The experiments were performed at the BL23SU of SPring-8. It is suggested that the C1s spectra is composed of at least three chemically-shifted components, which are assigned to carbon-poor Si$$_{1-x}$$C$$_{x}$$ alloy, carbon-rich Si$$_{1-x}$$C$$_{x}$$ alloy and 3C-SiC. The 3C-SiC nuclei began to generate at 8000s. Using C1s and Si2p$$_{3/2}$$ peaks, carbon concentration of the Si$$_{1-x}$$C$$_{x}$$ alloy layer was estimated to be about 0.17 of x. Therefore it is suggested that critical carbon concentration is 17%.

Journal Articles

Si(001) surface layer-by-layer oxidation studied by real-time photoelectron spectroscopy using synchrotron radiation

Ogawa, Shuichi*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Teraoka, Yuden; Takakuwa, Yuji*

Japanese Journal of Applied Physics, Part 1, 46(5B), p.3244 - 3254, 2007/05

 Times Cited Count:25 Percentile:68.99(Physics, Applied)

In this study, layer-by-layer oxidation at Si(001) surface was studied experimentally by real-time photoelectron spectroscopy. Changes of band bending due to oxidation-induced midgap states in connection with the oxygen uptake and changes in oxidation states were observed. Oxidation experiments were performed using the surface reaction analysis apparatus (SUREAC2000) installed at the BL23SU in the SPring-8. O 1s and Si 2p core level photoelectron spectra were measured alternately at acquisition times of 24 and 65 s, respectively. Curve-fitting analyses for them were carried out and two and seven components were found, respectively. On the basis of the observed changes of each oxidation state, the Si emission kinetics during layer-by-layer oxidation is discussed.

Journal Articles

Translational kinetic energy induced oxidation on Ti(0001) surfaces using a supersonic O$$_{2}$$ beam

Ogawa, Shuichi*; Takakuwa, Yuji*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Teraoka, Yuden; Moritani, Kosuke*; Mizuno, Yoshiyuki*

Denki Gakkai Rombunshi, C, 127(2), p.140 - 145, 2007/02

The initial sticking probability of O$$_{2}$$ molecule on a Ti(0001)-1$$times$$1 surface at room temperature was measured as a function of translational kinetic energy by real-time photoelectron spectroscopy. The O 1s photoelectron spectra can be fitted well with three components A, B, and C, where the chemical shift of component B and C are +0.7 and +1.6 eV relative to the binding energy of component A (528.8 eV). Upon exposing to the O$$_{2}$$ beam, component A and C appear dominantly and component B grows with an incubation time, indicating that two kinds of chemical adsorption states are concerned with dissociative adsorption of O$$_{2}$$ molecule at the initial stage. The incident energy dependence of initial sticking probability shows quite different behaviours between component A and C: initial sticking probability of component C decreases monotonously with incident energy and is almost constant above 0.6 eV, while initial sticking probability of component A shows a rapid decrease followed by a gradual increase with a minimum at 0.5 eV and then decreases with two small maxima at 0.9 and 1.8 eV. The observed incident energy dependence of initial sticking probability for component A and C are discussed in terms of a trapping-mediated dissociative adsorption and a direct dissociative adsorption process.

Journal Articles

Real-time photoelectron spectroscopy for Nitridation at Ti(0001) surface using supersonic N$$_{2}$$ molecular beams

Ogawa, Shuichi*; Takakuwa, Yuji*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Teraoka, Yuden; Mizuno, Yoshiyuki*

Shinku, 49(12), p.775 - 779, 2006/12

Nitridation on a Ti(0001)-1$$times$$1 surface using a supersonic N$$_{2}$$ molecular beam was investigated by real-time photoelectron spectroscopy to clarify the adsorption reaction dynamics of N$$_{2}$$ molecule on the Ti surface. In a whole N$$_{2}$$ dosage region examined, N 1s spectra can be fitted well with two chemically-shifted components, the binding energies of which are 396.9 and 396.6 eV, respectively. For both the components, the initial sticking probability S$$_{0}$$ shows a decrease with increasing incident energy in the overall trend, while has significant minima at 0.3 and 1.5 eV. Such incident energy dependences of S$$_{0}$$ suggest that the chemisorbed states are similarly caused by a trapping-mediated adsorption process through a physisorption state at lower incident energy than 0.3 eV and an activated adsorption process becomes dominant at higher incident energy than 0.3 eV.

Journal Articles

Consumption kinetics of Si atoms during growth and decomposition of very thin oxide on Si(001) surfaces

Ogawa, Shuichi*; Yoshigoe, Akitaka; Ishizuka, Shinji*; Teraoka, Yuden; Takakuwa, Yuji*

Thin Solid Films, 508(1-2), p.169 - 174, 2006/06

 Times Cited Count:11 Percentile:48.8(Materials Science, Multidisciplinary)

The surface morphological change during growth and subsequent decomposition of very thin oxide on Si(001) surface was observed in real time by RHEED combined with AES and macroscopically by STM. The RHEED intensity ratio between half-order spots revealed that etching of the surface took place in a manner of nucleation and lateral growth of dimer vacancy on the terrace during two-dimensional (2D) oxide island growth at 690$$^{circ}$$C, whereas the resultant oxide layer was decomposed at 709$$^{circ}$$C with consumption of Si atom in a step flow mode. STM observation of the partially oxide decomposed surface, however, showed that a number of Si islands with 10-20 angstrom in diameter remained randomly over the rather atomically flat terraces within voids in spite of the step-flow etching. These results are considered in terms of the phase separation of Si-rich oxide grown by 2D oxide island growth mode between Si clusters and a stoichiometric SiO$$_{2}$$ matrix and subsequent precipitation of Si islands on the terrace during decomposition.

Journal Articles

Growth kinetics of very thin oxide on Si and Ti surfaces studied by real-time surface analytical methods

Takakuwa, Yuji*; Ogawa, Shuichi*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Teraoka, Yuden

Journal of Surface Analysis, 13(1), p.36 - 84, 2006/04

no abstracts in English

Journal Articles

Surface chemical reaction dynamics illuminated by high brilliance and high energy-resolution synchrotron radiation; In-situ photoemission spectroscopy for surface oxidation induced by supersonic O$$_{2}$$ molecular beams

Teraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke; Takakuwa, Yuji*; Ogawa, Shuichi*; Ishizuka, Shinji*; Okada, Michio*; Fukuyama, Tetsuya*; Kasai, Toshio*

Hoshako, 18(5), p.298 - 309, 2005/09

Representative research results in surface reaction dynamics, performed at a surface chemistry experimental station installed in the JAEA soft X-ray beamline in the SPring-8, were reviewed. As a research result in JAEA, SiO desorption mechanisms in the Si(001) oxidation at high temperature were introduced. As a collaboration with Osaka University on oxidation reaction dynamics of Cu, collision-induced atom absorption process was introduced. As a collaboration with Tohoku University on Ti(0001) oxidation reaction dynamics, it was introduced that two peaks, found in an incident energy dependence of initial sticking probability, were corresponding to potential energy barriers of dissociative adsorption of O$$_{2}$$ molecules.

Journal Articles

Oxidation reaction kinetics on Ti(0001) surface studied by real-time photoelectron spectroscopy

Takakuwa, Yuji*; Ogawa, Shuichi*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Teraoka, Yuden

Shokubai, 47(5), p.352 - 357, 2005/08

Oxidation reactions of Ti(0001) surfaces were monitored by real-time photoelectron spectroscopy with high brilliant synchrotron radiation and He-I resonance line. An oxygen adsorption model and ultra-thin oxide layers formation processes were reviewed on the basis of time evolutions of the adsorbed oxygen amount, oxidation states, electronic states and the work function, which were obtained from photoelectron spectra for Ti 2p and O 1s core levels as well as the valence band.

103 (Records 1-20 displayed on this page)