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Cl dissociation, CH abstraction, and Cl adsorption from the dissociative scattering of supersonic CHCl on Cu(111) and Cu(410)Makino, Takamasa*; Tsuda, Yasutaka; Yoshigoe, Akitaka; Di
o, W. A.*; Okada, Michio*
Applied Surface Science, 642, p.158568_1 - 158568_6, 2024/01
Times Cited Count：0 Percentile：0.01(Chemistry, Physical)Terasawa, Tomoo; Matsunaga, Kazuya*; Hayashi, Naoki*; Ito, Takahiro*; Tanaka, Shinichiro*; Yasuda, Satoshi; Asaoka, Hidehito
Vacuum and Surface Science, 66(9), p.525 - 530, 2023/09
As Au (001) surfaces exhibit a quasi-one-dimensional corrugated structure, Hex-Au(001), its periodicity was predicted to change the electronic structure of graphene when graphene was grown on this surface. Furthermore, the hybridization between graphene and Au is known to introduce bandgap and spin polarization into graphene. Here, we report angle-resolved photoemission spectroscopy and density functional theory calculation of graphene on a Hex-Au(001) surface. A bandgap of 0.2 eV in the graphene Dirac cone was observed at the crossing point of the graphene Dirac cone and Au 6sp bands, indicating that the origin of the bandgap formation was the hybridization between the graphene Dirac cone and Au 6sp band. We discussed the hybridization mechanism and anticipated spin injection into the graphene Dirac cone.
Yasuda, Satoshi; Dio, W. A.*; Fukutani, Katsuyuki
Vacuum and Surface Science, 66(9), p.514 - 519, 2023/09
Monolayer graphene, representative of atomically thin crystals, has recently shown unexpectedly high proton and deuteron permeability under ambient conditions. It also permeates (filters) hydrogen (deuterium) isotope ion with high selectivity. These results suggest possible ways of developing novel and efficient hydrogen isotope gas enrichment techniques for manufacturing silicon semiconductors, optical fibers, drug development, nuclear fusion, and other related applications. And yet, despite its importance, experimental studies remain scarce and the separation mechanism contentious. Here, we introduce our recent findings on how quantum tunneling of hydrons through graphene could account for the high hydron selectivity of graphene.
Yamamoto, Kazami; Ogiwara, Norio*; Kuramochi, Masaya*
e-Journal of Surface Science and Nanotechnology (Internet), 21(4), p.359 - 364, 2023/07
In recent years, durable target is required according to increase of the beam power. To solve this problem, a liquid film was formed in vacuum and tested it as a target. An ethanol and a mercury were selected as liquid target materials, and we investigated whether the liquid sheet could be formed stably in a vacuum and how about the vacuum pressure. As a result, it was confirmed that the liquid films were stably formed in both case and the pressures with the films were about the vapor pressure of the materials.
Kamiya, Junichiro; Takano, Kazuhiro*; Wada, Kaoru; Yanagibashi, Toru*
e-Journal of Surface Science and Nanotechnology (Internet), 21(3), p.144 - 153, 2023/06
no abstracts in English
Kamiya, Junichiro; Nii, Keisuke*; Kabumoto, Hiroshi; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; Matsuda, Makoto; Moriya, Katsuhiro; Ida, Yoshiaki*; et al.
e-Journal of Surface Science and Nanotechnology (Internet), 21(4), p.344 - 349, 2023/05
no abstracts in English
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
Times Cited Count：3 Percentile：48.5(Chemistry, Physical)Immersion of graphene in KOH solution improves its mobility on SiO
/Si wafers. This is thought to be due to electron doping by modification with K atoms, but the K atom concentration C
in the graphene has not been clarified yet. In this study, the C was determined by XPS analysis using high-brilliance synchrotron radiation. The time evolution of C was determined by real-time observation, and the C 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.
(001) surface with supersonic seeded oxygen molecular beamKatsube, Daiki*; Ono, Shinya*; Inami, Eiichi*; Yoshigoe, Akitaka; Abe, Masayuki*
Vacuum and Surface Science, 65(11), p.526 - 530, 2022/11
The oxidation of oxygen vacancies at the surface of anatase TiO (001) was investigated by synchrotron radiation photoelectron spectroscopy and supersonic O beam (SSMB). The oxygen vacancies at the top surface and subsurface could be eliminated by the supply of hyperthermal oxygen molecules. Oxygen vacancies are present on the surface of anatase TiO(001) when it is untreated before transfer to a vacuum chamber. These vacancies, which are stable in the ambient condition, could also be effectively eliminated by using oxygen SSMB. This result is promising as a surface processing for various functional oxides.
molecule at SiO/Si(001) interface during Si dry oxidationTsuda, Yasutaka; Yoshigoe, Akitaka; Ogawa, Shuichi*; Sakamoto, Tetsuya*; Takakuwa, Yuji*
e-Journal of Surface Science and Nanotechnology (Internet), 21(1), p.30 - 39, 2022/11
Kawamura, Takaaki*; Fukaya, Yuki; Fukutani, Katsuyuki
Surface Science, 722, p.122098_1 - 122098_8, 2022/08
Times Cited Count：0 Percentile：0(Chemistry, Physical)no abstracts in English
Sekiguchi, Tetsuhiro; Yokoyama, Keiichi; Yaita, Tsuyoshi
e-Journal of Surface Science and Nanotechnology (Internet), 20(3), p.186 - 195, 2022/07
Cesium-135 having long life, 2.3 million y, that is contained in nuclear wastes may cause long-term pollution. Technology of isotopic separation of such long lived nuclide is indispensable not only for its volume reduction but also annihilation by nuclear transmutation. The recovery of atomic Cs from molecular CsI is mandatory. We have investigated fullerene C
as a potential absorber for Cs. Angle-resolved X-ray photoelectron spectroscopy, AR-XPS has been used to analyze the depth concentration distribution of Cs. Experiments were performed at soft X-ray beamline BL27A at KEK PF facility. We report on the annealing effect after deposition of Cs and the effect of heating substrate during deposition. For Cs/C sample, the intensity ratio of Cs-3d/C-1s increased in double at the high temperature. This suggests that Cs atoms remain in the material at high temperatures. On the other hand, for CsI/C, the intensity ratio does not change much by elevating temperatures.
Terasawa, Tomoo; Fukutani, Katsuyuki; Yasuda, Satoshi; Asaoka, Hidehito
e-Journal of Surface Science and Nanotechnology (Internet), 20(4), p.196 - 201, 2022/07
Graphene is a perfect impermeable membrane for gases but permeable to hydrogen ions. Hydrogen ion permeation shows the isotope effect, i.e., deuteron is slower than proton when permeating graphene. However, the permeation mechanism and the origin of the isotope effect are still unclear. Here, we propose a strategy to discuss the hydrogen ion permeation mechanism of graphene by developing an ion source with ultraslow, monochromatic, and mass-selected hydrogen ion beam. We employed a hemispherical monochromator and a Wien filter for the ion source to achieve the energy and mass resolutions of 0.39 eV and 1 atomic mass unit, respectively. The energetically sharp ion beam is expected to allow us to directly measure the permeability of graphene with high accuracy.
Tang, J.*; Seo, O.*; Rivera Rocabado, D. S.*; Koitaya, Takanori*; Yamamoto, Susumu*; Namba, Yusuke*; Song, C.*; Kim, J.*; Yoshigoe, Akitaka; Koyama, Michihisa*; et al.
Applied Surface Science, 587, p.152797_1 - 152797_8, 2022/06
Times Cited Count：7 Percentile：77.62(Chemistry, Physical)The hydrogen absorption and diffusion mechanisms on cube-shaped Pd nanoparticles (NPs) which are important hydrogen-storage materials were studied using X-ray photoelectron spectroscopy and DFT calculations. In the surface region, hydrogen absorption showed almost similar behavior regardless of the NPs size. It was found that the octahedral sites are more favorable than the tetrahedral sites for hydrogen occupation. We also clarified that the hydrogen atoms absorbing on the smaller-sized Pd NPs diffuse to the subsurface more actively because of the weakened Pd-H bond by the surface disordering, which plays an important role in hydrogen adsorption at a low H pressure.
complex as a possible origin of localized electron behavior in hydrogen-irradiated SrTiOIto, Takashi
e-Journal of Surface Science and Nanotechnology (Internet), 20(3), p.128 - 134, 2022/05
Kamiya, Junichiro; Takano, Kazuhiro*; Yuza, Hiromu*; Wada, Kaoru
e-Journal of Surface Science and Nanotechnology (Internet), 20(2), p.107 - 118, 2022/05
no abstracts in English
on Pd(210)Ueta, Hirokazu; Fukutani, Katsuyuki
Vacuum and Surface Science, 64(9), p.430 - 434, 2021/09
Te-based topological insulatorsSumida, Kazuki; Ishida, Yukiaki*; G
dde, J.*; H
fer, U.*; Shin, S.*; Kimura, Akio*
Progress in Surface Science, 96(2), p.100628_1 - 100628_15, 2021/05
Times Cited Count：2 Percentile：2.19(Chemistry, Physical)Ogawa, Shuichi*; Zhang, B.*; Yoshigoe, Akitaka; Takakuwa, Yuji*
Vacuum and Surface Science, 64(5), p.218 - 223, 2021/05
The oxidation reaction kinetics on Ti(0001) and Ni(111) surfaces were observed by real-time photoelectron spectroscopy using synchrotron radiation to measure the oxidation state and oxide thickness. After the Ti(0001) surface was wholly covered by TiO with a thickness of 1.2 nm, the rapid growth of n-type TiO proceeded through the diffusion of Ti
ions to the TiO surface at 400
C. A saturation of oxygen uptake on the TiO surface indicates that the O sticking coefficient on the TiO surface is negligibly small and the segregation of Ti to the TiO surface is a trigger to initiate the TiO growth. On the Ni(111) surface at 350C, a thermally stable NiO
proceeded preferentially and then the growth of p-type NiO was initiated. The time evolution of NiO thickness was represented by a logarithmic growth model, where the NiO growth is governed by the electron tunneling to the NiO surface.
-AlO
(0001)Entani, Shiro*; Honda, Mitsunori; Naramoto, Hiroshi*; Li, S.*; Sakai, Seiji*
Surface Science, 704, p.121749_1 - 121749_6, 2021/02
Times Cited Count：4 Percentile：33.7(Chemistry, Physical)Graphene is expected to be one of the most promising materials for nanoelectronics and spintronics. In most graphene-based devices, the graphene channel is placed on insulating substrates. Therefore, the study of inter-facial interactions between graphene and the insulator surface is of critical importance. In this study, the vertical arrangement of graphene which is transferred on -AlO(0001) has been studied by normal incidence X-ray standing wave (NIXSW) technique. The analysis of the NIXSW profile reveals that the graphene layer is located at 3.57 (
) above the -AlO(0001) surface, which is larger than the interlayer distance of graphite at 3.356 (). Micro- Raman spectroscopy shows that the transferred graphene has a limited spatial distribution of hole concentration. The present study shows that transferred graphene on the sapphire substrate followed by vacuum-annealing has an atomically flat surface free from residual contaminations such as organic compounds and there occurs the hole-doping in graphene.
measurement and analysis techniques in X-ray photoelectron spectroscopy; From NAP-HARPES to 4D-XPSToyoda, Satoshi*; Yamamoto, Tomoki*; Yoshimura, Masashi*; Sumida, Hirosuke*; Mineoi, Susumu*; Machida, Masatake*; Yoshigoe, Akitaka; Suzuki, Satoru*; Yokoyama, Kazushi*; Ohashi, Yuji*; et al.
Vacuum and Surface Science, 64(2), p.86 - 91, 2021/02
We have developed measurement and analysis techniques in X-ray photoelectron spectroscopy. To begin with, time-division depth profiles of gate stacked film interfaces have been achieved by NAP-HARPES (Near Ambient Pressure Hard X-ray Angle-Resolved Photo Emission Spectroscopy) data. We then have promoted our methods to quickly perform peak fittings and depth profiling from time-division ARPES data, which enables us to realize 4D-XPS analysis. It is found that the traditional maximum entropy method (MEM) combined with Jackknife averaging of sparse modeling in NAP-HARPES data is effective to perform dynamic measurement of depth profiles with high precision.
