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Nishiuchi, Mamiko; Choi, I. W.*; Daido, Hiroyuki; Nakamura, Tatsufumi*; Pirozhkov, A. S.; Yogo, Akifumi*; Ogura, Koichi; Sagisaka, Akito; Orimo, Satoshi; Daito, Izuru*; et al.
Plasma Physics and Controlled Fusion, 57(2), p.025001_1 - 025001_9, 2015/02
Times Cited Count：3 Percentile：13.75(Physics, Fluids & Plasmas)Projection images of a metal mesh produced by directional MeV electron beam together with directional proton beam, emitted simultaneously from a thin foil target irradiated by an ultrashort intense laser. The mesh patterns are projected to each detector by the electron beam and the proton beam originated from tiny virtual sources of 
20 micron meter and 10 micron meter diameters, respectively. Based on the observed quality and magnification of the projection images, we estimate sizes and locations of the virtual sources for both beams and characterize their directionalities. To carry out physical interpretation of the directional electron beam qualitatively, we perform 2D particle-in-cell simulation which reproduces a directional escaping electron component, together with a non-directional dragged-back electron component, the latter mainly contributes to building a sheath electric field for proton acceleration.
Abderrahmane, A.*; Takahashi, Hiroki*; Tashiro, Tatsuya*; Ko, P. J.*; Okada, Hiroshi*; Sato, Shinichiro; Oshima, Takeshi; Sandhu, A.*
AIP Conference Proceedings 1585, p.123 - 127, 2014/02
Times Cited Count：1 Percentile：51.08(Physics, Applied)The effect of annealing at 673 K on irradiated micro-Hall sensors irradiated with protons at 380 keV and fluences of 1
cm
, 1
cm, 1
cm is reported. Cathodoluminescence measurements were carried out at room temperature before and after annealing and showed improvement in the band edge band emission of the GaN layer. After annealing a sensor irradiated by 1 cm the device became operational with improvements in its magnetic sensitivity. All irradiated sensors showed improvement in their electrical characteristics after annealing.
/p-AlInGaP solar cellsLee, H. S.*; Yamaguchi, Masafumi*; Ekins-Daukes, N. J.*; Khan, A.*; Takamoto, Tatsuya*; Imaizumi, Mitsuru*; Oshima, Takeshi; Ito, Hisayoshi
Physica B; Condensed Matter, 376-377, p.564 - 567, 2006/04
Times Cited Count：2 Percentile：12.58(Physics, Condensed Matter)no abstracts in English
Oshima, Takeshi; Sumita, Taishi*; Imaizumi, Mitsuru*; Kawakita, Shiro*; Shimazaki, Kazunori*; Kuwajima, Saburo*; Oi, Akihiko*; Ito, Hisayoshi
Proceedings of 31st IEEE Photovoltaic Specialists Conference and Exhibition (PVSC-31), p.806 - 809, 2005/00
no abstracts in English
Sumita, Taishi*; Imaizumi, Mitsuru*; Oshima, Takeshi; Ito, Hisayoshi; Kuwajima, Saburo*
Proceedings of 31st IEEE Photovoltaic Specialists Conference and Exhibition (PVSC-31), p.667 - 670, 2005/00
no abstracts in English
Lee, H. S.*; Ekins-Daukes, N. J.*; Sasaki, Takuo*; Yamaguchi, Masafumi*; Khan, A.*; Takamoto, Tatsuya*; Agui, Takaaki*; Kamimura, Kunio*; Kaneiwa, Minoru*; Imaizumi, Mitsuru*; et al.
Proceedings of 31st IEEE Photovoltaic Specialists Conference and Exhibition (PVSC-31), p.556 - 558, 2005/00
no abstracts in English
Futakawa, Masatoshi
Shindo Gijutsu, (10), p.22 - 26, 2004/11
no abstracts in English
Chandrasekaran, N.*; Soga, Tetsuo*; Inuzuka, Yosuke*; Taguchi, Hironori*; Imaizumi, Mitsuru*; Oshima, Takeshi; Jimbo, Takashi*
Japanese Journal of Applied Physics, 43(10A), p.L1302 - L1304, 2004/10
Times Cited Count：6 Percentile：27.83(Physics, Applied)no abstracts in English
Iwata, Hiroshi*; Kagamihara, Satoshi*; Matsuura, Hideharu*; Kawakita, Shiro*; Oshima, Takeshi; Kamiya, Tomihiro
Proceedings of the 6th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-6), p.143 - 146, 2004/10
no abstracts in English
filmsOkada, Hiroshi*; Natsume, Satoshi*; Wakahara, Akihiro*; Yoshida, Akira*; Oshima, Takeshi; Kamiya, Tomihiro
Proceedings of the 6th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-6), p.147 - 150, 2004/10
no abstracts in English
thin filmsLee, H.-S.*; Okada, Hiroshi*; Wakahara, Akihiro*; Yoshida, Akira*; Oshima, Takeshi; Ito, Hisayoshi; Kawakita, Shiro*; Imaizumi, Mitsuru*; Matsuda, Sumio*
Physica Status Solidi (A), 199(3), p.471 - 474, 2003/10
Times Cited Count：3 Percentile：21.33(Materials Science, Multidisciplinary)no abstracts in English
Sumita, Taishi*; Imaizumi, Mitsuru*; Matsuda, Sumio*; Oshima, Takeshi; Oi, Akihiko; Ito, Hisayoshi
Nuclear Instruments and Methods in Physics Research B, 206, p.448 - 451, 2003/05
Times Cited Count：54 Percentile：94.59(Instruments & Instrumentation)Proton irradiation effects of triple-junction (InGaP/GaAs/Ge) solar cells for space use were studied. The changes in electrical and optical properties of the solar cells irradiated with protons at energies between 20 keV and 10 MeV were examined. As the result of analyzing the relationship between proton projection range and the degradation of their properties, the largest degradation of the properties was observed when proton projection range is near the junction of GaAs sub-cells. This indicates that improvement of the radiation resistance of GaAs is necessary to enhance radiation resistance of tliple-junction solar cells.
Oshima, Takeshi; Imaizumi, Mitsuru*; Takamoto, Tatsuya*; Sumita, Taishi*; Oi, Akihiko; Kawakita, Shiro*; Ito, Hisayoshi; Matsuda, Sumio*
Proceedings of 5th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications, p.113 - 116, 2002/10
The effects on proton and electron irradiateions of the characteristics of InGaP/GaAs/Ge triple junction designed for terrestrial application were studied. The solar cells used in this study has a 1% In-contained GaAs middle sub-cell, and their efficiency is more than 30 % under AM1.5, which is the highest efficiency of all solar cells in the world.As the results of 1MeV-electron and 10 MeV-proton irradiation, terrestrial triple-junction sole cells were found to have the same radiation resistance as space single junction GaAs solar cells, although terrestrial triple-junction solar cells is not stronger than space triple-junction solar cells made in USA. As the result of proton energy dependence of the electrical characteristics and quantum efficiency, the strong degradation of the GaAs middle cell was observed.
-InGaP space solar cellsDharmarasu, N.*; Yamaguchi, Masafumi*; Bourgoin, J. C.*; Takamoto, Tatsuya*; Oshima, Takeshi; Ito, Hisayoshi; Imaizumi, Mitsuru*; Matsuda, Sumio*
Applied Physics Letters, 81(1), p.64 - 66, 2002/07
Times Cited Count：17 Percentile：55.85(Physics, Applied)We studied the properties of observed defects in n/p-InGaP solar cells created by irradiation of protons with different energies.Three majority (hole) and a minority-carrier traps, labeled respectively as HP1 (E
+0.90
0.05eV), HP2 (E+0.730.05eV), H2 (E +0.55eV),and EP1 (E
0.54eV),were identified using deep level transient spectroscopy. All majority-carrier traps were found to act as recombination centers. While the H2 traps present in the proton-irradiated p-InGaP was found to anneal out by minority-carrier injection, the other traps were not.
thin-film solar cellsKawakita, Shiro*; Imaizumi, Mitsuru*; Yamaguchi, Masafumi*; Kushiya, Katsumi*; Oshima, Takeshi; Ito, Hisayoshi; Matsuda, Sumio*
Japanese Journal of Applied Physics, Part 2, 41(7A), p.L797 - L799, 2002/07
Recovery of electrical characteristics of Cu(In,Ga)Se irradiated with protons was studied. A proton irradiation chamber which has a AM0 solar light was used for in-situ measurement in this study. The electrical characteristics of irradiated samples which were kept under a dark condition recovered. Furthermore,this recovery effect was enhanced by light illumination. The activation energy for the recovery was estimated to be 0.80 eV (light illumination case) and 0.92 eV (dark condition case).
InGaP solar CellsDharmarasu, N.*; Khan, A.*; Yamaguchi, Masafumi*; Takamoto, Tatsuya*; Oshima, Takeshi; Ito, Hisayoshi; Imaizumi, Mitsuru*; Matsuda, Sumio*
Journal of Applied Physics, 91(5), p.3306 - 3311, 2002/03
Times Cited Count：25 Percentile：66.97(Physics, Applied)3MeV proton irradiation effects on InGaP single junction and InGaP/GaAs two junction cells were studied. The degradation of electrocal properties for InGaP cells was smaller than that for InGaP/GaAs cells. The results of the measurement of spectral response showed the large degradation in long wavelength. This indicates that GaAs cell degrades. The Damage coefficient of minority carrier diffusion length was estimated to be 7.9
10
for InGaP and 1.610
for GaAs. These values of the damage coefficient for InGaP and GaAs are 580 times and 280 times larger than those for InGaP and GaAs irradiated with 1MeV electrons.
/p InGaP solar cellDharmarasu, N.*; Yamaguchi, Masafumi*; Khan, K.*; Takamoto, Tatsuya*; Oshima, Takeshi; Ito, Hisayoshi; Imaizumi, Mitsuru*; Matsuda, Sumio*
Physica B; Condensed Matter, 308-310, p.1181 - 1184, 2001/12
Times Cited Count：7 Percentile：41.38(Physics, Condensed Matter)Carrier concentration and defects in n+/p InGaP irradiated with 100keV-protons (1E10, 5E12 /cm2) were studied.As a result of C-V measurements, the carrier removal rate was estimated to be 6.1E4 /cm2 which was extremely high as compared to 1MeV-electron irradiation case (0.93 /cm). H1 peak whose energy corresponds to Ev+0.90V was obtained from DLTS measurements. This suggests that carrier removal rate in proton-irradiated ones is much higher than that in electron-irradiated ones due to the generation of the defects (H1 peak) which act as majority carrier traps.
Dharmarasu, N.*; Yamaguchi, Masafumi*; Khan, A.*; Yamada, Takashi*; Tanabe, Tatsuya*; Takagishi, Shigenori*; Takamoto, Tatsuya*; Oshima, Takeshi; Ito, Hisayoshi; Imaizumi, Mitsuru*; et al.
Applied Physics Letters, 79(15), p.2399 - 2401, 2001/10
Times Cited Count：75 Percentile：90.93(Physics, Applied)The radiation response of 3MeV proton-irradiated InGaP, InGaAsP, and InGaAs solar cells was measured and analyzed in comparison with those of InP and GaAs. The degradation of the minority-carrier diffusion length was estimated from the spectral response. The damage coefficient K
for 3MeV proton-irradiated InGaP, InGaAsP and InGaAs was also determined. The radiation resistance increases with increase in the function of In-P bonds in those materials. Minority-carrier injection under forward bias is found to cause partial recovery of the degradation on irradiated InGaP and InGaAsP cells.
*; *; Matsuda, Sumio*; Oshima, Takeshi; Nashiyama, Isamu
Proceedings of 3rd International Workshop on Radiation Effects on Semiconductor Devices for Space Application, p.63 - 68, 1998/00
no abstracts in English
Sugimoto, Masayoshi; *; Kinsho, Michikazu; M.A.Chernogubovsky*; Maekawa, Hiroshi
NUP-A-96-10, 0, p.89 - 91, 1996/00
no abstracts in English
