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Entani, Shiro*; Honda, Mitsunori; Naramoto, Hiroshi*; Li, S.*; Sakai, Seiji*
Surface Science, 704, p.121749_1 - 121749_6, 2021/02
Times Cited Count:5 Percentile:33.23(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.
Entani, Shiro*; Honda, Mitsunori; Shimoyama, Iwao; Li, S.*; Naramoto, Hiroshi*; Yaita, Tsuyoshi; Sakai, Seiji*
Japanese Journal of Applied Physics, 57(4S), p.04FP04_1 - 04FP04_4, 2018/04
Times Cited Count:3 Percentile:13.53(Physics, Applied)Entani, Shiro; Naramoto, Hiroshi*; Sakai, Seiji
Journal of Applied Physics, 117(17), p.17A334_1 - 17A334_4, 2015/05
Times Cited Count:21 Percentile:63.75(Physics, Applied)Entani, Shiro; Antipina, L. Y.*; Avramov, P.*; Otomo, Manabu*; Matsumoto, Yoshihiro*; Hirao, Norie; Shimoyama, Iwao; Naramoto, Hiroshi*; Baba, Yuji; Sorokin, P. B.*; et al.
Nano Research, 8(5), p.1535 - 1545, 2015/05
Times Cited Count:28 Percentile:72.30(Chemistry, Physical)Kuzubov, A. A.*; Kovaleva, E. A.*; Avramov, P. V.*; Kuklin, A. V.*; Mikhaleva, N. S.*; Tomilin, F. N.*; Sakai, Seiji; Entani, Shiro; Matsumoto, Yoshihiro*; Naramoto, Hiroshi*
Journal of Applied Physics, 116(8), p.084309_1 - 084309_4, 2014/08
Times Cited Count:9 Percentile:36.99(Physics, Applied)Avramov, P. V.*; Kuzubov, A. A.*; Sakai, Seiji; Otomo, Manabu*; Entani, Shiro; Matsumoto, Yoshihiro*; Eleseeva, N. S.*; Pomogaev, V. A.*; Naramoto, Hiroshi*
Journal of Porphyrins and Phthalocyanines, 18(7), p.552 - 568, 2014/07
Times Cited Count:1 Percentile:5.07(Chemistry, Multidisciplinary)Otomo, Manabu; Yamauchi, Yasushi*; Kuzubov, A. A.*; Eliseeva, N. S.*; Avramov, P.*; Entani, Shiro; Matsumoto, Yoshihiro; Naramoto, Hiroshi*; Sakai, Seiji
Applied Physics Letters, 104(5), p.051604_1 - 051604_4, 2014/02
Times Cited Count:12 Percentile:45.92(Physics, Applied)Hexagonal boron nitride (h-BN) is a promising barrier material for graphene spintronics. In this study, spin-polarized metastable de-excitation spectroscopy (SPMDS) is employed to study the spin-dependent electronic structure of monolayer h-BN on Ni(111). The extreme surface sensitivity of SPMDS enables us to elucidate a partial filling of the in-gap states of h-BN without any superposition of Ni 3 signals. The in-gap states are shown to have a considerable spin polarization parallel to the majority spin of Ni. The positive spin polarization is attributed to the - hybridization and the effective spin transfer to the nitrogen atoms at the h-BN/Ni(111) interface.
Lavrentiev, V.*; Vorliek, V.*; Dejneke, A.*; Chvostova, D.*; Jger, A.*; Vacik, J.*; Jastrabik, L.*; Naramoto, Hiroshi*; Narumi, Kazumasa
Vacuum, 98, p.49 - 55, 2013/12
Times Cited Count:1 Percentile:4.47(Materials Science, Multidisciplinary)Matsumoto, Yoshihiro; Entani, Shiro; Koide, Akihiro*; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Amemiya, Kenta*; Fujikawa, Takashi*; Sakai, Seiji
Journal of Materials Chemistry C, 1(35), p.5533 - 5537, 2013/09
Times Cited Count:32 Percentile:76.07(Materials Science, Multidisciplinary)Sakai, Seiji; Matsumoto, Yoshihiro; Otomo, Manabu; Entani, Shiro; Avramov, P.; Sorokin, P. B.*; Naramoto, Hiroshi*
Synthetic Metals, 173, p.22 - 25, 2013/06
Times Cited Count:2 Percentile:9.67(Materials Science, Multidisciplinary)Narumi, Kazumasa; Naramoto, Hiroshi*; Yamada, Keisuke; Chiba, Atsuya; Saito, Yuichi; Maeda, Yoshihito
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 166, 2013/01
no abstracts in English
Avramov, P.; Kuzubov, A. A.*; Sakai, Seiji; Otomo, Manabu; Entani, Shiro; Matsumoto, Yoshihiro; Naramoto, Hiroshi*; Eliseeva, N. S.*
Journal of Applied Physics, 112(11), p.114303_1 - 114303_10, 2012/12
Times Cited Count:18 Percentile:58.48(Physics, Applied)Avramov, P.; Fedorov, D. G.*; Sorokin, P. B.*; Sakai, Seiji; Entani, Shiro; Otomo, Manabu; Matsumoto, Yoshihiro; Naramoto, Hiroshi*
Journal of Physical Chemistry Letters (Internet), 3(15), p.2003 - 2008, 2012/08
Times Cited Count:38 Percentile:79.32(Chemistry, Physical)Antipina, L. Y.*; Avramov, P.; Sakai, Seiji; Naramoto, Hiroshi*; Otomo, Manabu; Entani, Shiro; Matsumoto, Yoshihiro; Sorokin, P. B.*
Physical Review B, 86(8), p.085435_1 - 085435_7, 2012/08
Times Cited Count:54 Percentile:86.93(Materials Science, Multidisciplinary)Sakai, Seiji; Mitani, Seiji*; Matsumoto, Yoshihiro; Entani, Shiro; Avramov, P.; Otomo, Manabu; Naramoto, Hiroshi*; Takanashi, Koki
Journal of Magnetism and Magnetic Materials, 324(12), p.1970 - 1974, 2012/06
Times Cited Count:3 Percentile:14.19(Materials Science, Multidisciplinary)Entani, Shiro; Matsumoto, Yoshihiro; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Sakai, Seiji
Journal of Applied Physics, 111(6), p.064324_1 - 064324_6, 2012/03
Times Cited Count:21 Percentile:61.75(Physics, Applied)analysis was performed on the graphene growth in ultrahigh vacuum chemical vapor deposition by exposing the epitaxial Ni(111) thin film to benzene vapor at 873 K. It is shown that the highly uniform single- and bi-layer graphenes can be synthesized by the control of benzene exposure in the range of 10-10 langmuirs, reflecting a change in the graphene growth-rate by three orders of magnitude in between the first and second layer. Electron energy loss spectroscopy measurements of single- and bi-layer graphenes indicates that the interface interaction between bi-layer graphene and Ni(111) is weakened in comparison with that between single-layer graphene and Ni(111). It is also clarified from the micro-Raman analysis that the structural and electrical uniformities of the graphene film transformed on a SiO substrate are improved remarkably under the specific exposure conditions at which the growths of single- and bi-layer graphenes are completed.
Narumi, Kazumasa; Naramoto, Hiroshi*; Yamada, Keisuke; Saito, Yuichi; Chiba, Atsuya; Takahashi, Yasuyuki*; Maeda, Yoshihito
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 155, 2012/01
no abstracts in English
Matsumoto, Yoshihiro; Sakai, Seiji; Entani, Shiro; Takagi, Yasumasa*; Nakagawa, Takeshi*; Naramoto, Hiroshi*; Avramov, P.; Yokoyama, Toshihiko*
Chemical Physics Letters, 511(1-3), p.68 - 72, 2011/07
Times Cited Count:5 Percentile:15.93(Chemistry, Physical)X-ray magnetic circular dichroism (XMCD) spectroscopy was employed to investigate the electronic and magnetic structures of the bilayers of a C-Co compound and Ni. A few -several nm thick C-Co compound layers on the Ni(111) surface are found to show intense XMCD signals attributed to the localized Co d-spins only with the remanent magnetization of Ni layer. It is suggested that the region of the C-Co compound within 3 nm from the interface is ferromagnetically coupled with Ni due to the indirect exchange interaction mediated by C, probably relevant to the interlayer charge transfer.
Avramov, P.; Sakai, Seiji; Entani, Shiro; Matsumoto, Yoshihiro; Naramoto, Hiroshi*
Chemical Physics Letters, 508(1-3), p.86 - 89, 2011/05
Times Cited Count:25 Percentile:64.97(Chemistry, Physical)Sakai, Seiji; Mitani, Seiji*; Sugai, Isamu; Takanashi, Koki; Matsumoto, Yoshihiro; Entani, Shiro; Naramoto, Hiroshi*; Avramov, P.; Maeda, Yoshihito
Physical Review B, 83(17), p.174422_1 - 174422_6, 2011/05
Times Cited Count:8 Percentile:35.07(Materials Science, Multidisciplinary)