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Journal Articles

Single-photon emitting diode in silicon carbide

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:107 Percentile:96.88(Multidisciplinary Sciences)

Journal Articles

Coherent control of single spins in silicon carbide at room temperature

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:304 Percentile:99.5(Chemistry, Physical)

Journal Articles

Room temperature quantum emission from cubic silicon carbide nanoparticles

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

Journal Articles

A Silicon carbide room-temperature single-photon source

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:306 Percentile:99.39(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 (2$$times$$10$$^{6}$$ 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.

Journal Articles

Local thermal expansion and the C-C stretch vibration of the dicarbon antisite in 4H SiC

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:60.99

Journal Articles

Anharmonic vibrations of the dicarbon antisite defect in 4H-SiC

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:2 Percentile:10.06(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:34.04(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

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:8 Percentile:40.16(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

New lines and issues associated with deep defect spectra in electron, proton and $$^{4}$$He ion irradiated 4H SiC

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 $$^{4}$$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$$^{circ}$$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.

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:42.18(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

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.

Journal Articles

Identification of the negative Di-carbon antisite defect in n-type 4H-SiC

Gali, A.*; Umeda, Takahide*; Janz$'e$n, 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$$^{18}$$/cm$$^{2}$$ in temperature range between 300 and 800$$^{circ}$$C. As the results of ESR measurements, signals labeled HEI5 and HEI6, which have S=1/2 and C$$_{1h}$$ symmetry were observed. By the detailed measurements of $$^{29}$$Si and $$^{13}$$C hyperfine satellite, and first principle calculations, HEI5 and HEI6 were identified to be di-carbon antisite at cubic and hexagonal sites, respectively.

Journal Articles

Identification of divacancies in 4H-SiC

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:18.85(Physics, Condensed Matter)

no abstracts in English

Journal Articles

Identification of the carbon antisite-vacancy pair in 4${it H}$-SiC

Umeda, Takahide*; Son, N. T.*; Isoya, Junichi*; Janz$'e$n, 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:76 Percentile:91.18(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Divacancy in 4H-SiC

Son, N. T.*; Carlsson, P.*; Hassan, J. ul*; Janz$'e$n, 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:161 Percentile:96.79(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Shallow P donors in 3${it C}$-, 4${it H}$-, and 6${it H}$-SiC

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

Materials Science Forum, 527-529, p.593 - 596, 2006/00

no abstracts in English

Journal Articles

Divacancy model for P6/P7 centers in 4H- and 6H-SiC

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

Journal Articles

EPR and theoretical studies of positively charged carbon vacancy in 4$$H$$-SiC

Umeda, Takahide*; Isoya, Junichi*; Morishita, Norio; Oshima, Takeshi; Kamiya, Tomihiro; Gali, A.*; De$'a$k, P.*; Son, N. T.*; Janz$'e$n, E.*

Physical Review B, 70(23), p.235212_1 - 235212_6, 2004/12

 Times Cited Count:41 Percentile:83.61(Materials Science, Multidisciplinary)

no abstracts in English

Oral presentation

EPR and theoretical identification of di-carbon antisite defects in 4H-SiC

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

no journal, , 

no abstracts in English

Oral presentation

The Carbon vacancy in SiC

Son, N. T.*; Trinh, X. T.*; Suda, Jun*; Kimoto, Tsunenobu*; L${o}$vile, L. S.*; Svensson, B. G.*; Szasz, K.*; Hornos, T.*; Gali, A.*; Umeda, Takahide*; et al.

no journal, , 

no abstracts in English

22 (Records 1-20 displayed on this page)