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Lohrmann, A.*; Iwamoto, Naoya*; Bodrog, Z.*; Castelletto, S.*; Oshima, Takeshi; Karle, T. J.*; Gali, A.*; Prawer, S.*; McCallum, J. C.*; Johnson, B. C.*
Nature Communications (Internet), 6, p.7783_1 - 7783_7, 2015/07
Times Cited Count:160 Percentile:97.08(Multidisciplinary Sciences)Widmann, M.*; Lee, S.-Y.*; Rendler, T.*; Son, N. T.*; Fedder, H.*; Paik, S.*; Yang, L.-P.*; Zhao, N.*; Yang, S.*; Booker, I.*; et al.
Nature Materials, 14(2), p.164 - 168, 2015/02
Times Cited Count:484 Percentile:99.58(Chemistry, Physical)Castelletto, S.*; Johnson, B. C.*; Zachreson, C.*; Beke, D.*; Balogh, I.*; Oshima, Takeshi; Aharonovich, I.*; Gali, A.*
ACS Nano, 8(8), p.7938 - 7947, 2014/08
Times Cited Count:91 Percentile:90.51(Chemistry, Multidisciplinary)Castelletto, S.*; Johnson, B.*; Ivady, V.*; Stavrias, N.*; Umeda, Takahide*; Gali, A.*; Oshima, Takeshi
Nature Materials, 13(2), p.151 - 156, 2014/02
Times Cited Count:451 Percentile:99.46(Chemistry, Physical)The generation and detection of single photons play a central role in the experimental foundation of quantum mechanics and measurement theory. An effcient and high-quality single-photon source is thought to be necessary to realize quantum key distribution, quantum repeaters and photonic quantum information processing. We found the identication and formation of ultra-bright, room temperature, photo-stable single photon sources in silicon carbide (SiC). The single photon source consists of an intrinsic defect which is known as the carbon antisite vacancy pair, created by carefully optimized electron irradiation and annealing of ultra pure SiC. An extreme brightness (210
counts/s) resulting from polarization rules and a high quantum effciency is obtained in the bulk without resorting to the use of a cavity or plasmonic structure.
Devaty, R. P.*; Yan, F.*; Choyke, W. J.*; Gali, A.*; Kimoto, Tsunenobu*; Oshima, Takeshi
Materials Science Forum, 717-720, p.263 - 266, 2012/05
Times Cited Count:1 Percentile:52.89(Materials Science, Multidisciplinary)Yan, F.*; Devaty, R. P.*; Choyke, W. J.*; Gali, A.*; Kimoto, Tsunenobu*; Oshima, Takeshi; Pensl, G.*
Applied Physics Letters, 100(13), p.132107_1 - 132107_3, 2012/03
Times Cited Count:4 Percentile:17.62(Physics, Applied)Son, N. T.*; Gali, A.*; Szab,
.*; Bikermann, M.*; Oshima, Takeshi; Isoya, Junichi*; Janz
n, E.*
Applied Physics Letters, 98(24), p.242116_1 - 242116_3, 2011/06
Times Cited Count:11 Percentile:42.94(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 A nuclei with the hf splitting varying between
6.0 and
7.2 mT. By the Comparison between the hf data obtained from EPR and
supercell calculations, we concluded that the EI-1 defect is the best candidate for the neutral nitrogen vacancy in AlN.
Carlsson, P.*; Son, N. T.*; Gali, A.*; Isoya, Junichi*; Morishita, Norio; Oshima, Takeshi; Magnusson, B.*; Janzn, E.*
Physical Review B, 82(23), p.235203_1 - 235203_11, 2010/12
Times Cited Count:11 Percentile:44.94(Materials Science, Multidisciplinary)Electron Paramagnetic Resonance (EPR) studies of the EI4 center in 4- and 6
-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
C. An additional large-splitting
Si hf structure and
C hf lines of the EI4 defect were observed. Comparing the data obtained from the hf interactions and the annealing behavior, and also from
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
V
)
, as a new defect model for the EI4 center.
Yan, F.*; Devaty, R. P.*; Choyke, W. J.*; Kimoto, Tsunenobu*; Oshima, Takeshi; Pensl, G.*; Gali, A.*
Materials Science Forum, 645-648, p.411 - 414, 2010/00
Silicon Carbide (SiC) samples were irradiated with electron, proton and He ions and defects in the irradiated SiC were investigated by Low Temperature Photo Luminescence (LTPL). After irradiation, PL spectra between 2.48 and 2.62 eV were measured at 7 K. As a results, several PL lines were observed. These lines showed the same annealing behavior and were annealed out between 1300 and 1400
C. Therefore, it is concluded that these line have the same origin. In addition, as a result of simulation, the structure of the defect is determined to be di-carbon antisite.
Son, N. T.*; Janzn, 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:10 Percentile:41.50(Materials Science, Multidisciplinary)Defects in electron irradiated 3-SiC were studied by electron paramagnetic resonance EPR. The spectrum labeled LE1 was observed in
-type 3
SiC after electron irradiation at low temperatures (
80-100 K). Supercell calculations of different configurations of silicon vacancy-interstitial Frenkel-pairs, V
-Si
, 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
and a second neighbor Si
interstitial along the [100] direction in the 3+ charge state. In addition, a path for the migration of Si
was found in 3
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.
Gali, A.*; Umeda, Takahide*; Janzn, E.*; Morishita, Norio; Oshima, Takeshi; Isoya, Junichi*
Materials Science Forum, 615-617, p.361 - 364, 2009/00
Carbon antisite defects in Silicon Carbide (SiC) were studied using Electron Spin Resonance (ESR) and first principle calculations. The samples used in this study were n-type 4H-SiC, and these samples were irradiated with MeV electrons at 10/cm
in temperature range between 300 and 800
C. As the results of ESR measurements, signals labeled HEI5 and HEI6, which have S=1/2 and C
symmetry were observed. By the detailed measurements of
Si and
C hyperfine satellite, and first principle calculations, HEI5 and HEI6 were identified to be di-carbon antisite at cubic and hexagonal sites, respectively.
Son, N. T.*; Isoya, Junichi*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; Gali, A.*; Janzn, E.*
Materials Science Forum, 615-617, p.377 - 380, 2009/00
Defects introduced by electron irradiation at 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
symmetry and an electron spin S=3/2 could be determined to be the (V
-Si
)
Frenkel pair between the silicon vacancy and a second neighbor Si
interstitial along the
100
direction.
Son, N. T.*; Umeda, Takahide*; Isoya, Junichi*; Gali, A.*; Bockstedte, M.*; Magnusson, B.*; Ellison, A.*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; et al.
Physica B; Condensed Matter, 376-377, p.334 - 337, 2006/04
Times Cited Count:3 Percentile:17.26(Physics, Condensed Matter)no abstracts in English
Umeda, Takahide*; Son, N. T.*; Isoya, Junichi*; Janzn, E.*; Oshima, Takeshi; Morishita, Norio; Ito, Hisayoshi; Gali, A.*; Bockstedte, M.*
Physical Review Letters, 96(14), p.145501_1 - 145501_4, 2006/04
Times Cited Count:85 Percentile:90.89(Physics, Multidisciplinary)no abstracts in English
Son, N. T.*; Carlsson, P.*; Hassan, J. ul*; Janzn, E.*; Umeda, Takahide*; Isoya, Junichi*; Gali, A.*; Bockstedte, M.*; Morishita, Norio; Oshima, Takeshi; et al.
Physical Review Letters, 96(5), p.055501_1 - 055501_4, 2006/02
Times Cited Count:195 Percentile:97.04(Physics, Multidisciplinary)no abstracts in English
Son, N. T.*; Umeda, Takahide*; Isoya, Junichi*; Gali, A.*; Bockstedte, M.*; Magnusson, B.*; Ellison, A.*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; et al.
Materials Science Forum, 527-529, p.527 - 530, 2006/00
no abstracts in English
Isoya, Junichi*; Katagiri, Masayuki*; Umeda, Takahide*; Son, N. T.*; Henry, A.*; Gali, A.*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; Janzn, E.*
Materials Science Forum, 527-529, p.593 - 596, 2006/00
no abstracts in English
Umeda, Takahide*; Isoya, Junichi*; Morishita, Norio; Oshima, Takeshi; Kamiya, Tomihiro; Gali, A.*; Dek, P.*; Son, N. T.*; Janz
n, E.*
Physical Review B, 70(23), p.235212_1 - 235212_6, 2004/12
Times Cited Count:47 Percentile:84.32(Materials Science, Multidisciplinary)no abstracts in English
Umeda, Takahide*; Isoya, Junichi*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; Gali, A.*
no journal, ,
no abstracts in English
Son, N. T.*; Trinh, X. T.*; Suda, Jun*; Kimoto, Tsunenobu*; Lvile, L. S.*; Svensson, B. G.*; Szasz, K.*; Hornos, T.*; Gali, A.*; Umeda, Takahide*; et al.
no journal, ,
no abstracts in English