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Sumita, Takehiro; Sudo, Ayako; Takano, Masahide; Ikeda, Atsushi
Science and Technology of Advanced Materials; Methods (Internet), 2(1), p.50 - 54, 2022/02
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
Times Cited Count:4 Percentile:48.81(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 HO vapor has the highest reactivity due to the spin interaction between HO 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 AlGaN formation for p-GaN were observed at the interface of the AlO layer deposited by ALD using HO vapor. This study suggests that an oxidant gas other than HO and O should be used to avoid unintentional oxidation during AlGaN atomi layer deposition.
Kwon, H.*; Harjo, S.; Kawasaki, Takuro; Gong, W.; Jeong, S. G.*; Kim, E. S.*; Sathiyamoorthi, P.*; Kato, Hidemi*; Kim, H. S.*
Science and Technology of Advanced Materials, 23(1), p.579 - 586, 2022/00
Times Cited Count:6 Percentile:63.54(Materials Science, Multidisciplinary)Bendo, A.*; Matsuda, Kenji*; Nishimura, Katsuhiko*; Nunomura, Norio*; Tsuchiya, Taiki*; Lee, S.*; Marioara, C. D.*; Tsuru, Tomohito; Yamaguchi, Masatake; Shimizu, Kazuyuki*; et al.
Materials Science and Technology, 36(15), p.1621 - 1627, 2020/09
Times Cited Count:8 Percentile:46.23(Materials Science, Multidisciplinary)Metastable phases in aluminum alloys are the primary nano-scale precipitates which have the biggest contribution to the increase in the tangible mechanical properties. The continuous increase in hardness in the 7xxx aluminum alloys is associated with the phase transformation from clusters or GP-zones to the metastable phase. The transformation which is structural and compositional should occur following the path of the lowest activation energy. This work is an attempt to gain insight into how the structural transformation may occur based on the shortest route of diffusion for the eventual structure to result in that of phase. However, for the compositional transformation to occur, the proposed mechanism may not stand, since it is a prerequisite for the atoms to be at very precise positions in the aluminum lattice, at the very beginning of structural transformation, which may completely differ from that of the GP-zones atomic arrangements.
Fukuda, Kojiro*; Tomota, Yo*; Harjo, S.; Gong, W.*; Woo, W.*; Seong, B. S.*; Kuwahara, Yoshitaka*; Ikuta, Fumiaki*
Materials Science and Technology, 33(2), p.172 - 180, 2017/01
Times Cited Count:1 Percentile:5.53(Materials Science, Multidisciplinary)Tremsin, A. S.*; Gao, Y.*; Dial, L. C.*; Grazzi, F.*; Shinohara, Takenao
Science and Technology of Advanced Materials, 17(1), p.324 - 336, 2016/07
Times Cited Count:20 Percentile:55.84(Materials Science, Multidisciplinary)Oshima, Takeshi
Proceedings of the 30th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, p.9 - 16, 2011/12
no abstracts in English
Makino, Takahiro; Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi; Kobayashi, Daisuke*; Hirose, Kazuyuki*
Proceedings of the 28th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, p.35 - 40, 2009/12
We want to reveal the relation between SET-induced soft-error rates (s) and SET pulse-width distribution to be able to reduce the with an SET filter like an RC filter or a temporal latch architecture. By considering the relation between and SET pulse-width, we can determine the minimum time constant for the SET filter to reduce the effectively. A theoretical estimation has been proposed to obtain in a logic LSI from SET pulse-widths measured in logic cells and the latch probability of SET pulses at flip-flops (FFs) used in logic LSIs. However, the estimation method has not been verified yet. In this paper, we verify the theoretical estimation method.
Yokoya, Akinari; Shikazono, Naoya; Fujii, Kentaro; Ushigome, Takeshi*; Suzuki, Masao*; Urushibara, Ayumi; Watanabe, Ritsuko
Proceedings of the 27th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, 8 Pages, 2008/12
It has been indicated that ion particle irradiation to living cells causes a clustered DNA damage site, defined as two or more lesions formed within a few nano meters, in a cell nuclei. The clustered damage is less readily repaired by enzymatic repair system so that it induces biological effects, such as mutation induction. We have studied the mechanism of clustered damage induction by biochemical approaches using closed circular plasmid DNA as a model molecule to be irradiated with He ions from TIARA. We have used base excision repair proteins as enzymatic probes to quantify base lesions. We have also applied a novel method using DNA denaturation to visualize multiple single strand breaks which hardly be detected by conventional method. Our recent results will be reported in this seminar.
Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi
Proceedings of the 27th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, p.43 - 46, 2008/12
no abstracts in English
Sato, Shinichiro; Imaizumi, Mitsuru*; Oshima, Takeshi
Proceedings of the 27th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, p.37 - 42, 2008/12
Degradation modeling of triple junction (3J) solar cell due to proton and electron irradiation is performed with the use of a one dimensional optical device simulator. By fitting external quantum efficiencies of the 3J solar cells degraded by proton or electron irradiation, the short circuit current (Isc) and open circuit voltage (Voc) are simulated. These simulated values are in good accordance with the experimental data. In this modeling, carrier removal rate of base layer () and the damage coefficient of minority carrier diffusion length () in each sub cell are considered as radiation degradation parameters. NIEL (Non Ionizing Energy Loss) analysis for both radiation degradation parameters is discussed. The radiation degradation of a 3J solar cell can be predicted from correlativity between NIEL and radiation degradation parameters.
Onoda, Shinobu; Iwamoto, Naoya; Oshima, Takeshi; Hirao, Toshio; Kawano, Katsuyasu*
Proceedings of the 26th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, p.35 - 40, 2007/12
no abstracts in English
Iwamoto, Naoya; Oshima, Takeshi; Onoda, Shinobu; Hishiki, Shigeomi*; Murakami, Makoto; Nakano, Itsuo*; Kawano, Katsuyasu*
Proceedings of the 26th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, p.27 - 30, 2007/12
no abstracts in English
Oshima, Takeshi; Hishiki, Shigeomi*; Iwamoto, Naoya; Reshanov, S. A.*; Pensl, G.*; Kojima, Kazutoshi*; Kawano, Katsuyasu*
Proceedings of the 26th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, p.31 - 34, 2007/12
no abstracts in English
Kuroiwa, Sogo*; Takagiwa, Hiroyuki*; Yamazawa, Maki*; Akimitsu, Jun*; Koda, Akihiro*; Kadono, Ryosuke*; Oishi, Kazuki; Higemoto, Wataru; Watanabe, Isao*
Science and Technology of Advanced Materials, 7(1), p.12 - 16, 2006/01
Times Cited Count:5 Percentile:22.29(Materials Science, Multidisciplinary)The temperature dependence of muon spin relaxation rate exhibits a significant increase below 130 K in CaB and 110 K in BaB, while no sigh of spontaneous muon precession signal under a zero field is observed. Moreover, the electric field gradient at the boron site measured by muon level-crossing resonance exhibits a step like change at 110 K in CaB. These results suggest a change in electronic state and the associated emergence of weak random magnetism below 110-130 K in these alkaline earth hexaborides.
Yoshikawa, Masahito; *; Oshima, Takeshi; Ito, Hisayoshi; Nashiyama, Isamu; Okumura, Hajime*; Yoshida, Sadafumi*
14th Symp. on Materials Science and Engineering, Research Center of Ion Beam Technology, Hosei Univ., 0, p.159 - 165, 1996/00
no abstracts in English
Ito, Hisayoshi; Oshima, Takeshi; Aoki, Yasushi; Yoshikawa, Masahito; Nashiyama, Isamu; Okumura, Hajime*; Yoshida, Sadafumi*
14th Symp. on Materials Science and Engineering, Research Center of Ion Beam Technology, Hosei Univ., 0, p.147 - 150, 1995/00
no abstracts in English
Ito, Hisayoshi; Aoki, Yasushi; Yoshikawa, Masahito; Nashiyama, Isamu; Okumura, Hajime*; Yoshida, Sadafumi*
13th Symp. on Materials Science and Engineering, Research Center of Ion Beam Technology, Hosei Nniv., 0, p.75 - 80, 1994/12
no abstracts in English
Aoki, Yasushi; Namba, Hideki; Hosoi, Fumio; Nagai, Shiro
ACS Symposium Series, 579; Polymeric Materials for Microelectronic Applications,Science and Technology, 0, p.45 - 50, 1994/00
no abstracts in English