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Journal Articles

New application of NV centers in CVD diamonds as a fluorescent nuclear track detector

Onoda, Shinobu; Haruyama, Moriyoshi; Teraji, Tokuyuki*; Isoya, Junichi*; Kada, Wataru*; Hanaizumi, Osamu*; Oshima, Takeshi

Physica Status Solidi (A), 212(11), p.2641 - 2644, 2015/11

 Times Cited Count:6 Percentile:64.62(Materials Science, Multidisciplinary)

Journal Articles

NV centers in diamond used for detection of single ion track

Haruyama, Moriyoshi; Onoda, Shinobu; Kada, Wataru*; Teraji, Tokuyuki*; Isoya, Junichi*; Oshima, Takeshi; Hanaizumi, Osamu*

Proceedings of 11th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-11) (Internet), p.184 - 187, 2015/11

Journal Articles

Hydrogen at zinc vacancy of ZnO; An EPR and ESEEM study

Son, N. T.*; Isoya, Junichi*; Ivanov, I. G.*; Oshima, Takeshi; Janz$'e$n, E.*

AIP Conference Proceedings 1583, p.341 - 344, 2014/02

Journal Articles

Quantum error correction in a solid-state hybrid spin register

Waldherr, G.*; Wang, Y.*; Zaiser, S.*; Jamali, M.*; Schulte-Herbr$"u$ggen, T.*; Abe, Hiroshi; Oshima, Takeshi; Isoya, Junichi*; Du, J. F.*; Neumann, P.*; et al.

Nature, 506(7487), p.204 - 207, 2014/02

 Times Cited Count:276 Percentile:0.42(Multidisciplinary Sciences)

no abstracts in English

Journal Articles

Development of ion photon emission microscopy at JAEA

Onoda, Shinobu; Abe, Hiroshi; Yamamoto, Takashi; Oshima, Takeshi; Isoya, Junichi*; Teraji, Tokuyuki*; Watanabe, Kenji*

Proceedings of 10th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-10) (Internet), p.93 - 96, 2012/12

Journal Articles

Capacitance transient study of a bistable deep level in e$$^{-}$$-Irradiated n-type 4H-SiC

Beyer, F. C.*; Hemmingsson, C. G.*; Pedersen, H.*; Henry, A.*; Isoya, Junichi*; Morishita, Norio*; Oshima, Takeshi; Janz$'e$n, E.*

Journal of Physics D; Applied Physics, 45(45), p.455301_1 - 455301_7, 2012/11

 Times Cited Count:9 Percentile:57.47(Physics, Applied)

Journal Articles

Negative-U system of carbon vacancy in 4H-SiC

Son, N. T.*; Trinh, X. T.*; L${o}$vile, L. S.*; Svensson, B. G.*; Kawahara, Kotaro*; Suda, Jun*; Kimoto, Tsunenobu*; Umeda, Takahide*; Isoya, Junichi*; Makino, Takahiro; et al.

Physical Review Letters, 109(18), p.187603_1 - 187603_5, 2012/11

 Times Cited Count:152 Percentile:2.11(Physics, Multidisciplinary)

Journal Articles

Diamonds utilized in the development of single ion detector with high spatial resolution

Onoda, Shinobu; Yamamoto, Takashi; Oshima, Takeshi; Isoya, Junichi*; Teraji, Tokuyuki*; Watanabe, Kenji*

Transactions of the Materials Research Society of Japan, 37(2), p.241 - 244, 2012/06

Journal Articles

Electrically Detected Magnetic Resonance (EDMR) studies of SiC-SiO$$_{2}$$ interfaces

Umeda, Takahide*; Kosugi, Ryoji*; Fukuda, Kenji*; Morishita, Norio*; Oshima, Takeshi; Ezaki, Kana*; Isoya, Junichi*

Materials Science Forum, 717-720, p.427 - 432, 2012/05

 Times Cited Count:6 Percentile:4.04

Metal-Oxide (SiO$$_{2}$$)-Semiconductor (MOS) structures fabricated on Silicon Carbide (SiC) were studied using Electrically Detected Magnetic Resonance technique (EDMR). The residual Carbons are expected to be near the interface between SiC and SiC-SiO$$_{2}$$SiO$$_{2}$$, which is different from Si-SiO$$_{2}$$ interface. By the EDMR measurements at 50K, a defect center related to C dangling bonds which is called P$$_{H1}$$ center and also a center related to C dangling bonds terminated by hydrogens or nitrogens (Ns) which is called P$$_{H1}$$ were observed. In addition, a center related to N donor which is called Nh exist near the interface from N-treatment samples. This suggests that carrier concentration increases near the interface due to the introduction of donors, and as a result, the channel conductance increases.

Journal Articles

Behavior of nitrogen atoms in SiC-SiO$$_{2}$$ interfaces studied by electrically detected magnetic resonance

Umeda, Takahide*; Ezaki, Kana*; Kosugi, Ryoji*; Fukuda, Kenji*; Oshima, Takeshi; Morishita, Norio*; Isoya, Junichi*

Applied Physics Letters, 99(14), p.142105_1 - 142105_3, 2011/10

 Times Cited Count:43 Percentile:13.62(Physics, Applied)

Journal Articles

Defects at nitrogen site in electron-irradiated AlN

Son, N. T.*; Gali, A.*; Szab$'o$, $'A$.*; Bikermann, M.*; Oshima, Takeshi; Isoya, Junichi*; Janz$'e$n, E.*

Applied Physics Letters, 98(24), p.242116_1 - 242116_3, 2011/06

 Times Cited Count:7 Percentile:65.26(Physics, Applied)

AlN samples were irradiated with 2 MeV electrons, and defects in the AlN were measured using an electron paramagnetic resonance (EPR). As a result, a defect center, labeled EI-1, with an electron spin S=1/2 and a clear hyperfine hf structure was observed. The hf structure was shown to be the interaction between the electron spin and the nuclear spins of four $$^{27}$$A nuclei with the hf splitting varying between $$sim$$6.0 and $$sim$$7.2 mT. By the Comparison between the hf data obtained from EPR and ${it ab initio}$ supercell calculations, we concluded that the EI-1 defect is the best candidate for the neutral nitrogen vacancy in AlN.

Journal Articles

Annealing behavior of the EB-centers and M-center in low-energy electron irradiated $$n$$-type 4H-SiC

Beyer, F. C.*; Hemmingsson, C.*; Pedersen, H.*; Henry, A.*; Janz$'e$n, E.*; Isoya, Junichi*; Morishita, Norio*; Oshima, Takeshi

Journal of Applied Physics, 109(10), p.103703_1 - 103703_6, 2011/05

 Times Cited Count:9 Percentile:57.81(Physics, Applied)

By low-energy electron (200 keV) irradiation into epitaxial n-type 4H-SiC with a dose of 5$$times$$10$$^{16}$$/cm$$^{2}$$, the bistable M-center is detected in the deep level transient spectroscopy (DLTS) spectrum. The annealing behavior of the M-center is investigated. During the annihilation process of M-center, the bistable EB-centers are detected in the low temperature range of the DLTS spectrum. The value of annealing energy of the M-center is similar to the generation energy of the EB-centers. This suggests that the M-center partially transforms to the EB-centers by annealing. The EB-centers completely disappeared after annealing temperatures higher than 700 $$^{circ}$$C. Since the threshold energy for moving Si atom in SiC is higher than the applied irradiation energy of electrons, and the annihilation temperatures are relatively low, the M-center and the EB-centers are attributed to defects related to the C atom in SiC.

Journal Articles

EPR and ${it ab initio}$ calculation study on the EI4 center in 4$$H$$- and 6$$H$$-SiC

Carlsson, P.*; Son, N. T.*; Gali, A.*; Isoya, Junichi*; Morishita, Norio; Oshima, Takeshi; Magnusson, B.*; Janz$'e$n, E.*

Physical Review B, 82(23), p.235203_1 - 235203_11, 2010/12

 Times Cited Count:7 Percentile:62.79(Materials Science, Multidisciplinary)

Electron Paramagnetic Resonance (EPR) studies of the EI4 center in 4$$H$$- and 6$$H$$-Silicon Carbide (SiC) were carried out. The EI4 center was drastically enhanced in electron-irradiated high-purity semi-insulating materials by annealing at 700-750 $$^{circ}$$C. An additional large-splitting $$^{29}$$Si hf structure and $$^{13}$$C hf lines of the EI4 defect were observed. Comparing the data obtained from the hf interactions and the annealing behavior, and also from ${it ab initio}$ supercell calculations of different carbon-vacancy-related complexes, we propose a complex between a carbon vacancy-carbon antisite and a carbon vacancy at the third-neighbor site of the antisite in the neutral charge state, (V$$_{C}$$-C$$_{Si}$$V$$_{C}$$)$$^{0}$$, as a new defect model for the EI4 center.

Journal Articles

Fluorine-vacancy defects in fluorine-implanted silicon studied by electron paramagnetic resonance

Umeda, Takahide*; Isoya, Junichi*; Oshima, Takeshi; Onoda, Shinobu; Morishita, Norio; Okonogi, Kensuke*; Shiratake, Shigeru*

Applied Physics Letters, 97(4), p.041911_1 - 041911_3, 2010/07

 Times Cited Count:5 Percentile:74.02(Physics, Applied)

Journal Articles

The Carbon vacancy related EI4 defect in 4H SiC

Son, N. T.*; Carlsson, P.*; Isoya, Junichi*; Morishita, Norio; Oshima, Takeshi; Magnusson, B.*; Janz$'e$n, E.*

Materials Science Forum, 645-648, p.399 - 402, 2010/00

Defects in high-purity semi-insulating 4H SiC irradiated with 2 MeV electrons at room temperature were studied using Electron paramagnetic resonance (EPR). The EPR signal named EI4 defect increased with annealing temperature up to 750 $$^{circ}$$C. Additional large-splitting $$^{29}$$Si hyperfine (hf) structures and $$^{13}$$C hf lines by the interaction with one $$^{13}$$C nucleus were investigated. Based on the observed hf structures, the C$$_{1h}$$ symmetry as well as the annealing behaviour, the EI4 defects is determined to be the complex between two carbon vacancies and a carbon antisite in the neutral charge state, V$$_{C}$$V$$_{C}$$C$$_{Si}$$$$^{0}$$. The formation of the complex is interpreted in terms of the migration of the silicon vacancy and the formation of the carbon vacancy-carbon antisite pair next to a carbon vacancy.

Journal Articles

Metastable defects in low-energy electron irradiated n-type 4H-SiC

Beyer, F. C.*; Hemmingsson, C.*; Pedersen, H.*; Henry, A.*; Isoya, Junichi*; Morishita, Norio; Oshima, Takeshi; Janz$'e$n, E.*

Materials Science Forum, 645-648, p.435 - 438, 2010/00

By low-energy electron irradiation of epitaxial n-type 4H-SiC, the Deep Level Transient Spectroscopy (DLTS) peaks called the defects Z1/2 and EH6/7 were observed, which were also observed in as-grown layer and the commonly found peaks EH1 and EH3 (M-center) also appeared. New defect named the EB-centers increased after annealing out of EH1 and EH3. Since low energy electron irradiation (less than 220 keV) affects mainly the carbon atom in SiC, both the M- and EB-centers might be carbon related defects.

Journal Articles

Identification of the gallium vacancy-oxygen pair defect in GaN

Son, N. T.*; Hemmingsson, C. G.*; Paskova, T.*; Evans, K. R.*; Usui, Akira*; Morishita, Norio; Oshima, Takeshi; Isoya, Junichi*; Monemar, B.*; Janz$'e$n, E.*

Physical Review B, 80(15), p.153202_1 - 153202_4, 2009/10

 Times Cited Count:35 Percentile:20.11(Materials Science, Multidisciplinary)

GaN samples were irradiated with electrons of 2 MeV at 1$$times$$10$$^{19}$$/cm$$^{2}$$, and electron spin resonance (ESR) was measured at 77 K. As a result, four defect signals which are labeled D1 to D4 were observed. The D2 signal was identified to be negatively charged gallium vacancy - oxygen pair from the details studies of $$^{14}$$N hf structure.

Journal Articles

Identification of a Frenkel-pair defect in electron-irradiated 3$$C$$ SiC

Son, N. T.*; Janz$'e$n, E.*; Isoya, Junichi*; Morishita, Norio; Hanaya, Hiroaki; Takizawa, Haruki; Oshima, Takeshi; Gali, A.*

Physical Review B, 80(12), p.125201_1 - 125201_8, 2009/09

 Times Cited Count:9 Percentile:57.26(Materials Science, Multidisciplinary)

Defects in electron irradiated 3$$C$$-SiC were studied by electron paramagnetic resonance EPR. The spectrum labeled LE1 was observed in $$n$$-type 3$$C$$ SiC after electron irradiation at low temperatures ($$sim$$80-100 K). Supercell calculations of different configurations of silicon vacancy-interstitial Frenkel-pairs, V$$_{rm Si}$$-Si$$_{rm i}$$, were carried out. Comparing the data obtained from experiments using EPR and supercell calculations, the LE1 center is assigned to the Frenkel-pair between V$$_{rm Si}$$ and a second neighbor Si$$_{rm i}$$ interstitial along the [100] direction in the 3+ charge state. In addition, a path for the migration of Si$$_{rm i}$$$$^{4+}$$ was found in 3$$C$$ SiC. In samples electron-irradiated at low temperatures, the LE1 Frenkel-pair was found to be the dominating defect whereas EPR signals of single vacancies were not detected. The center disappears after warming up the samples to room temperature.

Journal Articles

Photo-EPR study of vacancy-type defects in irradiated ${it n}$-type 4${it H}$-SiC

Umeda, Takahide*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; Isoya, Junichi*

Materials Science Forum, 600-603, p.409 - 412, 2009/00

We have performed photo-electron paramagnetic resonance (photo-EPR) analyses on four types of fundamental vacancy-related defects in 3MeV electron-irradiated 4${it H}$-SiC, i.e., carbon vacancies $$V$$$$_{rm C}$$$$^{-}$$), silicon vacancies ($$T$$$$_{V2a}$$-type $$V$$$$_{rm Si}$$$$^{-}$$), divacancies $$V$$$$_{rm Si}$$$$V$$$$_{rm C}$$$$^{0/-}$$), and carbon antisite-vacancy pairs (C$$_{rm Si}$$$$V$$$$_{rm C}$$$$^{-}$$). The photo-induced transitions from their -2 to -1 charged states or from their -1 charged to neutral states were detected in the photon energy range between 0.80 and 1.20 eV. Based on these transitions, we have discussed positions of their defect levels with respect to the conduction band edge.

Journal Articles

Defects introduced by electron-irradiation at low temperatures in SiC

Son, N. T.*; Isoya, Junichi*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; Gali, A.*; Janz$'e$n, E.*

Materials Science Forum, 615-617, p.377 - 380, 2009/00

Defects introduced by electron irradiation at $$sim$$ 80-100 K in 3C-, 4H- and 6H-Silicon Carbide (SiC) were investigated by Electron Paramagnetic Resonance (EPR). A number of EPR spectra, labelled LE1-10, were detected. Combining EPR and theoretical calculations (supercell calculation), the LE1 center in 3C-SiC with C$$_{2v}$$ symmetry and an electron spin S=3/2 could be determined to be the (V$$_{Si}$$-Si$$_{i}$$)$$^{3+}$$ Frenkel pair between the silicon vacancy and a second neighbor Si$$_{i}$$ interstitial along the $$<$$ 100 $$>$$ direction.

86 (Records 1-20 displayed on this page)