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Zhao, Y.*; Suzuki, T.*; Iimori, T.*; Kim, H.-W.*; Ahn, J. R.*; Horio, Masafumi*; Sato, Yusuke*; Fukaya, Yuki; Kanai, T.*; Okazaki, K.*; et al.
Physical Review B, 105(11), p.115304_1 - 115304_8, 2022/03
Times Cited Count：1 Percentile：6.98(Materials Science, Multidisciplinary)no abstracts in English
Fukaya, Yuki; Zhao, Y.*; Kim, H.-W.*; Ahn, J.-R.*; Fukidome, Hirokazu*; Matsuda, Iwao*
Physical Review B, 104(18), p.L180202_1 - L180202_5, 2021/11
Times Cited Count：17 Percentile：70.83(Materials Science, Multidisciplinary)no abstracts in English
Hasegawa, Mika*; Sugawara, Kenta*; Suto, Ryota*; Sambonsuge, Shota*; Teraoka, Yuden; Yoshigoe, Akitaka; Filimonov, S.*; Fukidome, Hirokazu*; Suemitsu, Maki*
Nanoscale Research Letters, 10, p.421_1 - 421_6, 2015/10
Times Cited Count：21 Percentile：60.72(Nanoscience & Nanotechnology)Graphene has attracted much attention as a promising material in electronics and photonics. The graphitization temperature of 1473 K or higher of graphene-on-silicon(GOS), however, is still too high to be fully compatible with the Si technology. Here, the first application of Ni-assisted formation of graphene to the GOS method was reported. We demonstrate that the graphene formation temperature can be reduced by more than 200 K by this method. Moreover, solid-phase reactions during heating/annealing/cooling procedures have been investigated in detail by using 
synchrotron-radiation X-ray photoelectron spectroscopy. As a result, we clarify the role of Ni/SiC reactions, in which not only Ni silicidation and but also Ni carbonization is suggested as a key process in the formation of graphene.
Suemitsu, Maki*; Fukidome, Hirokazu*; Teraoka, Yuden
NanotechJapan Bulletin (Internet), 7(2), 5 Pages, 2014/04
no abstracts in English
Ide, Takayuki*; Kawai, Yusuke*; Handa, Hiroyuki*; Fukidome, Hirokazu*; Kotsugi, Masato*; Okochi, Takuo*; Enta, Yoshiharu*; Kinoshita, Toyohiko*; Yoshigoe, Akitaka; Teraoka, Yuden; et al.
Japanese Journal of Applied Physics, 51(6), p.06FD02_1 - 06FD02_4, 2012/06
Times Cited Count：7 Percentile：29.19(Physics, Applied)Fukidome, Hirokazu*; Abe, Shunsuke*; Takahashi, Ryota*; Imaizumi, Kei*; Inomata, Shuya*; Handa, Hiroyuki*; Saito, Eiji*; Enta, Yoshiharu*; Yoshigoe, Akitaka; Teraoka, Yuden; et al.
Applied Physics Express, 4(11), p.115104_1 - 115104_3, 2011/11
Times Cited Count：36 Percentile：77.75(Physics, Applied)Fukidome, Hirokazu*; Takahashi, Ryota*; Abe, Shunsuke*; Imaizumi, Kei*; Handa, Hiroyuki*; Kang, H. C.*; Karasawa, Hiromi*; Suemitsu, Tetsuya*; Otsuji, Taiichi*; Enta, Yoshiharu*; et al.
Journal of Materials Chemistry, 21(43), p.17242 - 17248, 2011/11
Times Cited Count：29 Percentile：62.59(Chemistry, Physical)Takahashi, Ryota*; Handa, Hiroyuki*; Abe, Shunsuke*; Imaizumi, Kei*; Fukidome, Hirokazu*; Yoshigoe, Akitaka; Teraoka, Yuden; Suemitsu, Maki*
Japanese Journal of Applied Physics, 50(7), p.070103_1 - 070103_6, 2011/07
Times Cited Count：32 Percentile：74.73(Physics, Applied)Imaizumi, Kei*; Handa, Hiroyuki*; Takahashi, Ryota*; Saito, Eiji*; Fukidome, Hirokazu*; Enta, Yoshiharu*; Teraoka, Yuden; Yoshigoe, Akitaka; Suemitsu, Maki*
Japanese Journal of Applied Physics, 50(7), p.070105_1 - 070105_6, 2011/07
Times Cited Count：4 Percentile：18.25(Physics, Applied)Haramoto, Naoki*; Inomata, Shuya*; Takahashi, Ryota*; Yoshigoe, Akitaka; Teraoka, Yuden; Fukidome, Hirokazu*; Suemitsu, Maki*
no journal, ,
no abstracts in English
Hasegawa, Mika*; Yoshigoe, Akitaka; Sugawara, Kenta*; Suto, Ryota*; Sambonsuge, Shota*; Teraoka, Yuden; Fukidome, Hirokazu*; Suemitsu, Maki*
no journal, ,
Low-temperature (1073 K) formation of graphene was performed on Si substrates by using an ultrathin (2 nm) Ni layer deposited on a 3C-SiC thin film heteroepitaxially grown on a Si substrate. Angle-resolved, synchrotron-radiation X-ray photoemission spectroscopy (SR-XPS) results show that the stacking order is, from the surface to the bulk, Ni carbides(Ni
C/NiCx)/graphene/Ni/Ni silicides (Ni
Si/NiSi)/3C-SiC/Si. In situ SR-XPS during the graphitization annealing clarified that graphene is formed during the cooling stage. We conclude that Ni silicide and Ni carbide formation play an essential role in the formation of graphene.
Fukidome, Hirokazu*; Miyamoto, Yu*; Handa, Hiroyuki*; Takahashi, Ryota*; Imaizumi, Kei*; Suemitsu, Maki*; Yoshigoe, Akitaka; Teraoka, Yuden
no journal, ,
Graphene, two-dimensional network of sp
carbon, is one of promising materials beyond CMOS, as described in the semiconductor roadmap. The major issue is a lack of reasonable process for epitaxial growth on substrates. In fact, current production methods, such as exfoliation from graphite and epitaxy on SiC single crystals, are not mass-productive. We are seeking the ways to develop graphene-on-silicon (3D-GOS) process to match recent trends of silicon technologies. One of key issues toward 3D-GOS is the formation of epitaxial graphene on main plane directions of silicon, such as (100), (110) and (111). In this article, large area epitaxy of graphene on Si(110), Si(100) and Si(111) is presented. The result must be a good news because it can open new and realistic ways to three-dimensionally fabricate graphene-based devices beyond CMOS.
Takahashi, Ryota*; Miyamoto, Yu*; Handa, Hiroyuki*; Saito, Eiji*; Imaizumi, Kei*; Fukidome, Hirokazu*; Suemitsu, Maki*; Teraoka, Yuden; Yoshigoe, Akitaka
no journal, ,
We have succeeded to form graphene films from 3C-SiC layer on Si substrate by thermal annealing in vacuum (graphene on silicon technique:GOS). In this study, surface structures were observed by LEED and XPS methods to make clear the GOS formation mechanisms. SiC-1
1 LEED pattern was observed at 3C-SiC(111) surface on the Si substrate showing periodicity of bulk SiC. After graphene formation treatments of 1523 K thermal annealing for 30 min, graphene 11 pattern was observed showing periodicity of graphene. The graphene (11) spots were tilted by 30 deg comparing to the bulk SiC (11) spots. C1s-XPS observation revealed that a peak corresponding to sp bonding increased with decreasing SiC bulk peak. Consequently, graphene formation from 3C-SiC on Si substrate is same as that on 6H-SiC(0001) substrate.
Imaizumi, Kei*; Takahashi, Ryota*; Miyamoto, Yu*; Handa, Hiroyuki*; Saito, Eiji*; Fukidome, Hirokazu*; Suemitsu, Maki*; Teraoka, Yuden; Yoshigoe, Akitaka
no journal, ,
As the graphene, 2D-crystal of a carbon atomic layer, has a large mobility of 300000 cm/V/s, it is expected as a candidate for the next generation electronic device material. As to the practical use of graphene, a graphene-on-silicon (GOS) technique in which graphene is formed by thermal annealling on an silicon substrate covered by an SiC thin film. Since the anneal temperature is high as 1523-1573 K for the graphene formation in the former techniques including the GOS technique, such a high temperature technique is not introduced indeed in silicon device fabrication processes. We noticed a temperature-pressure phase diagram reported by Yongwei Song et al.. We have succeeded to form a graphene film on the SiC surface at a lower temperature of 1273 K by adding a bit of oxygen gas in the anneal atmosphere.
Imaizumi, Kei*; Takahashi, Ryota*; Handa, Hiroyuki*; Saito, Eiji*; Fukidome, Hirokazu*; Suemitsu, Maki*; Teraoka, Yuden; Yoshigoe, Akitaka
no journal, ,
We found that an SiC surface changed to a graphene film even at 1273 K in the oxygen gas ambient. As subsequent experiments, real-time photoelectron spectroscopy using synchrotron radiation was applied to observe the graphene formation process in the ultra low pressure oxygen ambient. The 3C-SiC(111) surface, formed on the Si(111) surface using monomethylsilane, was used as a substrate. The real-time photoelectron spectroscopy was performed at BL23SU in the SPring-8. With increasing reaction time, a C1s photoelectron peak originated from sp carbon increased. It reveals that a graphene film is formed on the SiC surface.
Takahashi, Ryota*; Miyamoto, Yu*; Handa, Hiroyuki*; Saito, Eiji*; Imaizumi, Kei*; Fukidome, Hirokazu*; Suemitsu, Maki*; Teraoka, Yuden; Yoshigoe, Akitaka
no journal, ,
New technologies beyond Si-CMOS technologies are neccessary in the Si electronic device developments. Now, graphene is attracted as it has a large mobility. It is well known that a 6H-SiC substrate surface changes to graphene by thermal annealing in vacuum as Si atoms sublimate. On the other hand, we developed the graphene-on-silicon (GOS) method in which graphene is formed from 3C-SiC thin film on an Si substrate by thermal annealing in vacuum. In this report, graphene formation processes were observed by LEED for a 6H-SiC(0001) substrate and a 3C-SiC(111) surface. It was found that the graphene formation process on a 3C-SiC(111) surface proceeded through the same surface reconstruction structure with that of 6H-SiC(0001) substrate.
Haramoto, Naoki*; Inomata, Shuya*; Takahashi, Ryota*; Yoshigoe, Akitaka; Teraoka, Yuden; Fukidome, Hirokazu*; Suemitsu, Maki*
no journal, ,
Hasegawa, Mika*; Sugawara, Kenta*; Suto, Ryota*; Sambonsuge, Shota*; Haramoto, Naoki*; Teraoka, Yuden; Yoshigoe, Akitaka; Fukidome, Hirokazu*; Suemitsu, Maki*
no journal, ,
no abstracts in English
Hasegawa, Mika*; Sugawara, Kenta*; Suto, Ryota*; Sambonsuge, Shota*; Haramoto, Naoki*; Teraoka, Yuden; Yoshigoe, Akitaka; Fukidome, Hirokazu*; Suemitsu, Maki*
no journal, ,
no abstracts in English
Takahashi, Ryota*; Handa, Hiroyuki*; Abe, Shunsuke*; Inomata, Shuya*; Imaizumi, Kei*; Fukidome, Hirokazu*; Teraoka, Yuden; Yoshigoe, Akitaka; Kotsugi, Masato*; Okochi, Takuo*; et al.
no journal, ,
no abstracts in English
