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Your search keyword '"Takeuchi, T."' showing total 24 results
Start Over Author "Takeuchi, T." Journal applied physics letters
24 results on '"Takeuchi, T."'

3. Reduced nonradiative recombination rates in c-plane Al0.83In0.17N films grown on a nearly lattice-matched GaN substrate by metalorganic vapor phase epitaxy.

Author

Li, L. Y., Shima, K., Yamanaka, M., Kojima, K., Egawa, T., Uedono, A., Ishibashi, S., Takeuchi, T., Miyoshi, M., and Chichibu, S. F.

Subjects
GALLIUM nitride, CHARGE carrier lifetime, EPITAXY, POINT defects, GASES, SUPERLATTICES
Abstract

A record-long room-temperature photoluminescence (PL) lifetime ( τ PL RT ) of approximately 70 ps was obtained for the sub-bandgap 3.7 eV emission band of a 300-nm-thick c-plane Al0.83In0.17N epilayer for the use in cladding layers of an edge laser structure, which were grown by metalorganic vapor phase epitaxy on a low threading dislocation density nearly lattice-matched GaN substrate. The recorded τ PL RT value was twice as long as previously reported ones, indicating half concentration of nonradiative recombination centers. Room-temperature spatially resolved cathodoluminescence intensity images for the 3.7 eV band revealed nearly zero carrier diffusion length, which is consistent with the fact that τ PL RT of 70 ps is 1/35 of the near-band-edge emission of the GaN substrate (2.4 ns). As the PL decay curves for the 3.7 eV band were sufficiently fitted by the stretched exponential function, the emission likely originates from extended states such as impurities, point defects, and their complexes, as well as localized states of uneven potential profile. [ABSTRACT FROM AUTHOR]

Published
2021
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4. Strain effects in Nb3Al multifilamentary conductors prepared by phase transformation from bcc supersaturated-solid solution

Author

Takeuchi, T., Iijima, Y., Inoue, K., Wada, H., ten Haken, Bernard, ten Kate, Herman H.J., Fukuda, K., Iwaki, G., Sakai, S., Moriai, H., and Faculty of Science and Technology

Subjects
Supersaturation, Fabrication, Materials science, Physics and Astronomy (miscellaneous), Strain (chemistry), Metallurgy, Phase (matter), IR-98125, Composite material, METIS-129264, Type-II superconductor, Electrical conductor, Stoichiometry, Solid solution
Abstract

Strain effects on critical current densities have been examined for conductors containing nearly stoichiometric Nb3Al filaments with fine grains. The Nb3Al phase in these multifilamentary conductors are prepared by phase transformation from supersaturated Nb(Al) bcc solid solution and show high-field critical current densities much larger than those for conventionally prepared Nb3Al conductors, where the Nb3Al phase is known to be off-stoichiometric. The degradation of critical current densities with −0.7% intrinsic strain is ca. 20% at 12 T, comparable with those for conventional Nb3Al conductors of high strain tolerance.

Published
1997

7. Design and performance analysis of deep-etch air/nitride distributed Bragg reflector gratings for AlInGaN laser diodes

Author

Marinelli, C., primary, Bordovsky, M., additional, Sargent, L. J., additional, Gioannini, M., additional, Rorison, J. M., additional, Penty, R. V., additional, White, I. H., additional, Heard, P. J., additional, Benyoucef, M., additional, Kuball, M., additional, Hasnain, G., additional, Takeuchi, T., additional, and Schneider, R. P., additional

Published
2001
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12. Improvement of far-field pattern in nitride laser diodes

Author

Takeuchi, T., primary, Detchprohm, T., additional, Iwaya, M., additional, Hayashi, N., additional, Isomura, K., additional, Kimura, K., additional, Yamaguchi, M., additional, Amano, H., additional, Akasaki, I., additional, Kaneko, Yw., additional, Shioda, R., additional, Watanabe, S., additional, Hidaka, T., additional, Yamaoka, Y., additional, Kaneko, Ys., additional, and Yamada, N., additional

Published
1999
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19. Strain effects in Nb[sub 3]Al multifilamentary conductors prepared by phase transformation from....

Author

Takeuchi, T., Iijima, Y., Inoue, K., Wada, H., ten Haken, B., ten Kate, H.H.J., Fukuda, K., Iwaki, G., Sakai, S., and Moriai, H.

Subjects
*STRAINS & stresses (Mechanics), *SUPERCONDUCTORS, *CRITICAL currents
Abstract

Examines the strain effects on critical current densities for conductors with stoichiometric Nb[sub 3]Al filaments. Preparation of the filaments by phase transformation; Comparison of strain sensitivity among different conductors; Degradation of critical current densities.

Published
1997
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20. Pinning mechanism in a continuous ultrafine Nb3Al multifilamentary superconductor.

Author

Takeuchi, T., Iijima, Y., Kosuge, M., Inoue, K., Watanabe, K., and Noto, K.

Subjects
*NIOBIUM compounds, *SUPERCONDUCTORS, *PHYSICS
Abstract

For Nb3Al multifilamentary superconductors fabricated by a newly developed composite process using continuous ultrafine Al-based alloy cores and pure Nb matrix, Jc properties have been investigated in detail in regard to the size and morphology of the Al core. A significant enhancement in pinning force caused by reducing the Al core size and an anisotropy in Jc observed in a rolled tape have indicated that the Nb3Al-matrix (or core) interface acts as a dominant pinning center of fluxoids. [ABSTRACT FROM AUTHOR]

Published
1988
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