JAEA
  • help
  • PC | SP
  • JP | EN
          
Refine your search：     
Report No.
 - 
Clear All
Search Results: Records 1-20 displayed on this page of 163

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

Dissociative adsorption of supersonic CH$$_{3}$$Cl on Cu oxide Surfaces; Cu$$_{2}$$O(111) and bulk Cu$$_{2}$$O precursor "29"; Structure on Cu(111)

Hayashida, Koki*; Tsuda, Yasutaka; Murase, Natsumi*; Yamada, Takashi*; Yoshigoe, Akitaka; Di$~n$o, W. A.*; Okada, Michio*

Applied Surface Science, 669, p.160475_1 - 160475_6, 2024/10

https://doi.org/10.1016/j.apsusc.2024.160475

Journal Articles

CH$$_3$$Cl dissociation, CH$$_3$$ abstraction, and Cl adsorption from the dissociative scattering of supersonic CH$$_3$$Cl on Cu(111) and Cu(410)

Makino, Takamasa*; Tsuda, Yasutaka; Yoshigoe, Akitaka; Di$~n$o, W. A.*; Okada, Michio*

Applied Surface Science, 642, p.158568_1 - 158568_6, 2024/01

https://doi.org/10.1016/j.apsusc.2023.158568
 Times Cited Count：0 Percentile：0.01(Chemistry, Physical)

Journal Articles

Work function lowering of LaB$$_{6}$$ by monolayer hexagonal boron nitride coating for improved photo- and thermionic-cathodes

Yamaguchi, Hisato*; Yusa, Ryunosuke*; Wang, G.*; Pettes, M. T.*; Liu, F.*; Tsuda, Yasutaka; Yoshigoe, Akitaka; Abukawa, Tadashi*; Moody, N. A.*; Ogawa, Shuichi*

Applied Physics Letters, 122(14), p.141901_1 - 141901_7, 2023/04

https://doi.org/10.1063/5.0142591
 Times Cited Count：3 Percentile：78.44(Physics, Applied)

A lowering of work function for LaB$$_{6}$$ by monolayer hexagonal BN coating is reported. Photoemission electron microcopy (PEEM) and thermionic emission electron microscopy (TEEM) both revealed that the hBN coated region of a LaB$$_{6}$$(100) single crystal has lower work function compared to the bare (i.e., non-coated) and graphene coated regions. A larger decrease of work function for the hBN coated LaB$$_{6}$$(100) compared to graphene coated LaB$$_{6}$$(100) was qualitatively supported by our density functional theory (DFT) calculations. Adding an oxide layer in the calculations improved consistency between the calculation and experimental results. We followed up our calculations with synchrotron-radiation X-ray photoelectron spectroscopy (SR-XPS) and confirmed the presence of an oxide layer on our LaB$$_{6}$$.

Journal Articles

Leading edge of semiconductors

Tsuda, Yasutaka

Nihonkai Shimbun, P. 7, 2023/02

no abstracts in English

Journal Articles

Evaluation of doped potassium concentrations in stacked two-Layer graphene using real-time XPS

Ogawa, Shuichi*; Tsuda, Yasutaka; Sakamoto, Tetsuya*; Okigawa, Yuki*; Masuzawa, Tomoaki*; Yoshigoe, Akitaka; Abukawa, Tadashi*; Yamada, Takatoshi*

Applied Surface Science, 605, p.154748_1 - 154748_6, 2022/12

https://doi.org/10.1016/j.apsusc.2022.154748
 Times Cited Count：4 Percentile：54.33(Chemistry, Physical)

Immersion of graphene in KOH solution improves its mobility on SiO$$_{2}$$/Si wafers. This is thought to be due to electron doping by modification with K atoms, but the K atom concentration C$$_{K}$$ in the graphene has not been clarified yet. In this study, the C$$_{K}$$ was determined by XPS analysis using high-brilliance synchrotron radiation. The time evolution of C$$_{K}$$ was determined by real-time observation, and the C$$_{K}$$ before irradiation of synchrotron radiation was estimated to be 0.94%. The C 1s spectrum shifted to the low binding energy side with the desorption of K atoms. This indicates that the electron doping concentration into graphene is decreasing, and it is experimentally confirmed that K atoms inject electrons into graphene.

Journal Articles

Roles of excess minority carrier recombination and chemisorbed O$$_{2}$$ species at SiO$$_{2}$$/Si interfaces in Si dry oxidation; Comparison between p-Si(001) and n-Si(001) surfaces

Tsuda, Yasutaka; Yoshigoe, Akitaka; Ogawa, Shuichi*; Sakamoto, Tetsuya*; Yamamoto, Yoshiki*; Yamamoto, Yukio*; Takakuwa, Yuji*

Journal of Chemical Physics, 157(23), p.234705_1 - 234705_21, 2022/12

https://doi.org/10.1063/5.0109558
 Times Cited Count：0 Percentile：0.01(Chemistry, Physical)

Journal Articles

Observation of chemisorbed O$$_2$$ molecule at SiO$$_2$$/Si(001) interface during Si dry oxidation

Tsuda, Yasutaka; Yoshigoe, Akitaka; Ogawa, Shuichi*; Sakamoto, Tetsuya*; Takakuwa, Yuji*

e-Journal of Surface Science and Nanotechnology (Internet), 21(1), p.30 - 39, 2022/11

https://doi.org/10.1380/ejssnt.2023-005

Journal Articles

Probing copper and copper-gold alloy surfaces with space-quantized oxygen molecular beam

Tsuda, Yasutaka; Gueriba, J. S.*; Ueta, Hirokazu*; Di$~n$o, W. A.*; Kurahashi, Mitsunori*; Okada, Michio*

JACS Au (Internet), 2(8), p.1839 - 1847, 2022/08

https://doi.org/10.1021/jacsau.2c00156

Journal Articles

High reactivity of H$$_{2}$$O vapor on GaN surfaces

Sumiya, Masatomo*; Sumita, Masato*; Tsuda, Yasutaka; Sakamoto, Tetsuya; Sang, L.*; Harada, Yoshitomo*; Yoshigoe, Akitaka

Science and Technology of Advanced Materials, 23(1), p.189 - 198, 2022/00

https://doi.org/10.1080/14686996.2022.2052180
 Times Cited Count：4 Percentile：46.76(Materials Science, Multidisciplinary)

GaN is an attracting material for power-electronic devices. Understanding the oxidation at GaN surface is important for improving metal-oxide-semiconductor (MOS) devices. In this study, the oxidation at GaN surfaces depending on the GaN crystal planes (+c, -c, and m-plane) was investigated by real time XPS and DFT-MD simulation. We found that H$$_{2}$$O vapor has the highest reactivity due to the spin interaction between H$$_{2}$$O and GaN surfaces. The bond length between the Ga and N on the -c GaN surface was increased by OH attacking the back side of three-fold Ga atom. The chemisorption on the m-plane was dominant. The intense reactions of oxidation and Al$$_{x}$$Ga$$_{1-x}$$N formation for p-GaN were observed at the interface of the Al$$_{2}$$O$$_{3}$$ layer deposited by ALD using H$$_{2}$$O vapor. This study suggests that an oxidant gas other than H$$_{2}$$O and O$$_{2}$$ should be used to avoid unintentional oxidation during Al$$_{x}$$Ga$$_{1-x}$$N atomi layer deposition.

Journal Articles

Revisit of XPS studies of supersonic O$$_{2}$$ molecular adsorption on Cu(111); Copper oxides

Hayashida, Koki*; Tsuda, Yasutaka; Yamada, Takashi*; Yoshigoe, Akitaka; Okada, Michio*

ACS Omega (Internet), 6(40), p.26814 - 26820, 2021/10

https://doi.org/10.1021/acsomega.1c04663
 Times Cited Count：7 Percentile：47.89(Chemistry, Multidisciplinary)

We report the X-ray photoemission spectroscopy (XPS) characterization of the bulk Cu$$_{2}$$O(111) surface and 8-type and 29-type oxide structures on Cu(111) prepared by using 0.5 eV O$$_{2}$$ supersonic molecular beam (SSMB) source. We propose a new structural model for the 8-type oxide structure and also confirmed the previously proposed model for the [29] oxide structure on Cu(111), based on the O1s XPS spectra. The detection-angle dependence of the O 1s spectra supports that the nanopyramidal model is more preferable for the ($$sqrt{3}$$X$$sqrt{3}$$)R30$$^{circ}$$ Cu$$_{2}$$O(111). We also report the electronic excitations which O1s electrons suffer.

Journal Articles

Oxidation of anatase TiO$$_{2}$$(001) surface using supersonic seeded oxygen molecular beam

Katsube, Daiki*; Ono, Shinya*; Takayanagi, Shuhei*; Ojima, Shoki*; Maeda, Motoyasu*; Origuchi, Naoki*; Ogawa, Arata*; Ikeda, Natsuki*; Aoyagi, Yoshihide*; Kabutoya, Yuito*; et al.

Langmuir, 37(42), p.12313 - 12317, 2021/10

https://doi.org/10.1021/acs.langmuir.1c01752
 Times Cited Count：1 Percentile：6.17(Chemistry, Multidisciplinary)

We investigated the oxidation of oxygen vacancies at the surface of anatase TiO$$_{2}$$(001) using supersonic seeded molecular beam (SSMB) of oxygen. The oxygen vacancies at the top-surface and sub-surface could be eliminated by the supply of oxygen using an SSMB. These results indicate that the interstitial vacancies can be mostly assigned to oxygen vacancies, which can be effectively eliminated by using an oxygen SSMB. Oxygen vacancies are present on the surface of anatase TiO$$_{2}$$(001) when it is untreated before transfer to a vacuum chamber. These vacancies, which are stable in the as-grown condition, could also be effectively eliminated using the oxygen SSMB.

Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

https://doi.org/10.1038/s41550-020-01271-2
 Times Cited Count：44 Percentile：96.99(Astronomy & Astrophysics)

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Journal Articles

Interface atom mobility and charge transfer effects on CuO and Cu$$_{2}$$O formation on Cu$$_{3}$$Pd(111) and Cu$$_{3}$$Pt(111)

Tsuda, Yasutaka; Gueriba, J. S.*; Makino, Takamasa*; Di$~n$o, W. A.*; Yoshigoe, Akitaka; Okada, Michio*

Scientific Reports (Internet), 11, p.3906_1 - 3906_8, 2021/02

https://doi.org/10.1038/s41598-021-82180-w
 Times Cited Count：3 Percentile：14.79(Multidisciplinary Sciences)

Journal Articles

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.

Science, 364(6437), p.272 - 275, 2019/04

https://doi.org/10.1126/science.aav7432
 Times Cited Count：262 Percentile：99.73(Multidisciplinary Sciences)

The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

Journal Articles

Oxidation processes of copper-gold alloy surface induced by supersonic oxygen molecular beam

Okada, Michio*; Tsuda, Yasutaka*; Yoshigoe, Akitaka; Di$~n$o, W. A.*

Do To Dogokin, 56(1), p.232 - 236, 2017/00

We reported the our studies on the surface temperature (Ts) dependence of oxidation on the Cu$$_{3}$$Au(111) surface by a supersonic O$$_{2}$$ molecular beam, using synchrotron radiation X-ray photoemission spectroscopy. Clean surface shows strong Au segregation to the top layer, i.e., Au surface enrichment of the clean surface. Complete Cu segregation to the surface occurs at 0.5 ML O surface coverage. The Au-rich second and third layers of the oxidized surface demonstrate the protective layer formation against oxidation deeper into the bulk. We found that Cu$$_{2}$$O formation occurs. At Ts = 300K, the Cu$$_{2}$$O growth is not so effective. The surface oxidation is less effective on Cu$$_{3}$$Au(111) than on Cu(111). At Ts = 400K, the protection by the Au-rich layer against oxidation into bulk is effective. At Ts = 500K, the Au protective layer is broken due to effective Au diffusion and thus Cu$$_{2}$$O grows deeper into bulk.

Journal Articles

Experimental and theoretical studies on oxidation of Cu-Au alloy surfaces; Effect of bulk Au concentration

Okada, Michio*; Tsuda, Yasutaka*; Oka, Kohei*; Kojima, Kazuki*; Di$~n$o, W. A.*; Yoshigoe, Akitaka; Kasai, Hideaki*

Scientific Reports (Internet), 6, p.31101_1 - 31101_8, 2016/08

https://doi.org/10.1038/srep31101
 Times Cited Count：28 Percentile：73.15(Multidisciplinary Sciences)

We report results of our experimental and theoretical studies on the oxidation of Cu-Au alloy surfaces, viz., Cu$$_{3}$$Au(111), CuAu(111), and Au$$_{3}$$Cu(111), using hyperthermal O$$_{2}$$ molecular beam (HOMB). We observed strong Au segregation to the top layer of the corresponding clean (111) surfaces. This forms a protective layer that hinders further oxidation into the bulk. The higher the concentration of Au in the protective layer formed, the higher the protective efficacy. As a result, of the three Cu-Au surfaces studied, Au$$_{3}$$Cu(111) is the most stable against dissociative adsorption of O$$_{2}$$, even with HOMB. We also found that this protective property breaks down for oxidations occurring at temperatures above 300 K.

Journal Articles

Surface temperature dependence of oxidation of Cu$$_{3}$$Au(111) by an energetic oxygen molecule

Tsuda, Yasutaka*; Yoshigoe, Akitaka; Teraoka, Yuden; Okada, Michio*

Materials Research Express (Internet), 3(3), p.035014_1 - 035014_8, 2016/03

https://doi.org/10.1088/2053-1591/3/3/035014
 Times Cited Count：5 Percentile：18.55(Materials Science, Multidisciplinary)

We report a study on the surface-temperature ($$T_{s}$$) dependence of oxidation process at Cu$$_{3}$$Au(111) by using a hyperthermal oxygen molecular beam and synchrotron-radiation X-ray photoemission spectroscopy. The O-1s spectra and the corresponding O-uptake curves demonstrate that Cu$$_{2}$$O domains grow effectively at high $$T_{s}$$ of 400 and 500 K. The simple analysis of the O distribution suggests that the temperature-induced atomic diffusion causes the Cu$$_{2}$$O domains growing thicker at 500 K. The oxidation of Cu$$_{3}$$Au(111) is less efficient at $$T_{s}$$ = 300-500 K than that of Cu(111), demonstrating that the protective nature of Cu$$_{3}$$Au against oxidation, in comparison to Cu, remains even at high $$T_{s}$$.

Journal Articles

The Effects of alloying and segregation for the reactivity and diffusion of oxygen on Cu$$_{3}$$Au(111)

Oka, Kohei*; Tsuda, Yasutaka*; Makino, Takamasa*; Okada, Michio*; Hashinokuchi, Michihiro*; Yoshigoe, Akitaka; Teraoka, Yuden; Kasai, Hideaki*

Physical Chemistry Chemical Physics, 16(36), p.19702 - 19711, 2014/08

https://doi.org/10.1039/C4CP02675F
 Times Cited Count：11 Percentile：39.91(Chemistry, Physical)

Journal Articles

Initial stages of Cu$$_{3}$$Au(111) oxidation; Oxygen induced Cu segregation and the protective Au layer profile

Tsuda, Yasutaka*; Oka, Kohei*; Makino, Takamasa*; Okada, Michio*; Di$~n$o, W. A.*; Hashinokuchi, Michihiro*; Yoshigoe, Akitaka; Teraoka, Yuden; Kasai, Hideaki*

Physical Chemistry Chemical Physics, 16(8), p.3815 - 3822, 2014/02

https://doi.org/10.1039/c3cp54709d
 Times Cited Count：14 Percentile：48.54(Chemistry, Physical)

Journal Articles

Electron cyclotron heating applied to the JT-60U tokamak

Hoshino, Katsumichi; Suzuki, Takahiro; Isayama, Akihiko; Ide, Shunsuke; Takenaga, Hidenobu; Kubo, Hirotaka; Fujita, Takaaki; Kamada, Yutaka; Fujii, Tsuneyuki; Tsuda, Takashi; et al.

Fusion Science and Technology, 53(1), p.114 - 129, 2008/01

https://doi.org/10.13182/FST08-A1659
 Times Cited Count：2 Percentile：16.93(Nuclear Science & Technology)

We report on the applications of the ECH to the JT-60U tokamak. The ECH contributes to the advanced tokamak study in JT-60U in such respects as (1)NTM suppression, (2)Study on the internal transport barrier, (3)Impurity exhaust, (4)Tokamak start-up without center solenoid, (5)Current hole study, (6)Confinement and transport study, and (7)Start-up and shut-down assist. These contributions comes from the good local coupling of the ECH to the tokamak plasma.

163 (Records 1-20 displayed on this page)