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Journal Articles

Switching of major nonradiative recombination centers (NRCs) from carbon impurities to intrinsic NRCs in GaN crystals

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K. Sano, H. Fujikura, T. Konno, S. Kaneki, S. Ichikawa, K. Kojima
Journal: Applied Physics Letters
Appl. Phys. Lett. 124, 231101 (2024)
https://doi.org/10.1063/5.0207339
Published: June 2024
View articletitled, Switching of major nonradiative recombination centers (NRCs) from carbon impurities to intrinsic NRCs in GaN crystals
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Journal Articles

Improved minority carrier lifetime in p-type GaN segments prepared by vacancy-guided redistribution of Mg

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K. Shima, R. Tanaka, S. Takashima, K. Ueno, M. Edo, K. Kojima, A. Uedono, S. Ishibashi, S. F. Chichibu
Journal: Applied Physics Letters
Appl. Phys. Lett. 119, 182106 (2021)
https://doi.org/10.1063/5.0066347
Published: November 2021
View articletitled, Improved minority carrier lifetime in p-type GaN segments prepared by vacancy-guided redistribution of Mg
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Journal Articles

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

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L. Y. Li, K. Shima, M. Yamanaka, K. Kojima, T. Egawa, A. Uedono, S. Ishibashi, T. Takeuchi, M. Miyoshi, S. F. Chichibu
Journal: Applied Physics Letters
Appl. Phys. Lett. 119, 091105 (2021)
https://doi.org/10.1063/5.0066263
Published: August 2021
View articletitled, Reduced nonradiative recombination rates in c-plane Al0.83In0.17N films grown on a nearly lattice-matched GaN substrate by metalorganic vapor phase epitaxy
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Journal Articles

Urbach–Martienssen tail as the origin of the two-peak structure in the photoluminescence spectra for the near-band-edge emission of a freestanding GaN crystal observed by omnidirectional photoluminescence spectroscopy

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K. Kojima, S. F. Chichibu
Journal: Applied Physics Letters
Appl. Phys. Lett. 117, 171103 (2020)
https://doi.org/10.1063/5.0028134
Published: October 2020
View articletitled, Urbach–Martienssen tail as the origin of the two-peak structure in the photoluminescence spectra for the near-band-edge emission of a freestanding GaN crystal observed by omnidirectional photoluminescence spectroscopy
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Journal Articles

Observation of carrier lifetime distribution in 4H-SiC thick epilayers using microscopic time-resolved free carrier absorption system

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K. Nagaya, T. Hirayama, T. Tawara, K. Murata, H. Tsuchida, A. Miyasaka, K. Kojima, T. Kato, H. Okumura, M. Kato
Journal: Journal of Applied Physics
J. Appl. Phys. 128, 105702 (2020)
https://doi.org/10.1063/5.0015199
Published: September 2020
View articletitled, Observation of carrier lifetime distribution in 4H-SiC thick epilayers using microscopic time-resolved free carrier absorption system
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Journal Articles

Self-organized micro-light-emitting diode structure for high-speed solar-blind optical wireless communications

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K. Kojima, Y. Yoshida, M. Shiraiwa, Y. Awaji, A. Kanno, N. Yamamoto, A. Hirano, Y. Nagasawa, M. Ippommatsu, S. F. Chichibu
Journal: Applied Physics Letters
Appl. Phys. Lett. 117, 031103 (2020)
https://doi.org/10.1063/5.0013112
Published: July 2020
View articletitled, Self-organized micro-light-emitting diode structure for high-speed solar-blind optical wireless communications
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Journal Articles

In-plane optical polarization and dynamic properties of the near-band-edge emission of an m-plane freestanding AlN substrate and a homoepitaxial film

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S. F. Chichibu, K. Kojima, K. Hazu, Y. Ishikawa, K. Furusawa, S. Mita, R. Collazo, Z. Sitar, A. Uedono
Journal: Applied Physics Letters
Appl. Phys. Lett. 115, 151903 (2019)
https://doi.org/10.1063/1.5116900
Published: October 2019
View articletitled, In-plane optical polarization and dynamic properties of the near-band-edge emission of an m-plane freestanding AlN substrate and a homoepitaxial film
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Journal Articles

Internal quantum efficiency of radiation in a bulk CH3NH3PbBr3 perovskite crystal quantified by using the omnidirectional photoluminescence spectroscopy

Editor’s PickOpen Access
K. Kojima, K. Ikemura, K. Matsumori, Y. Yamada, Y. Kanemitsu, S. F. Chichibu
Journal: APL Materials
APL Mater. 7, 071116 (2019)
https://doi.org/10.1063/1.5110652
Published: July 2019
View articletitled, Internal quantum efficiency of radiation in a bulk CH3NH3PbBr3 perovskite crystal quantified by using the omnidirectional photoluminescence spectroscopy
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Journal Articles

Carrier localization structure combined with current micropaths in AlGaN quantum wells grown on an AlN template with macrosteps

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K. Kojima, Y. Nagasawa, A. Hirano, M. Ippommatsu, Y. Honda, H. Amano, I. Akasaki, S. F. Chichibu
Journal: Applied Physics Letters
Appl. Phys. Lett. 114, 011102 (2019)
https://doi.org/10.1063/1.5063735
Published: January 2019
View articletitled, Carrier localization structure combined with current micropaths in AlGaN quantum wells grown on an AlN template with macrosteps
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Journal Articles

Room-temperature photoluminescence lifetime for the near-band-edge emission of (000 1 ¯ ) p-type GaN fabricated by sequential ion-implantation of Mg and H

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K. Shima, H. Iguchi, T. Narita, K. Kataoka, K. Kojima, A. Uedono, S. F. Chichibu
Journal: Applied Physics Letters
Appl. Phys. Lett. 113, 191901 (2018)
https://doi.org/10.1063/1.5050967
Published: November 2018
View articletitled, Room-temperature photoluminescence lifetime for the near-band-edge emission of (000 1 ¯ ) p-type GaN fabricated by sequential ion-implantation of Mg and H
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Journal Articles

Large electron capture-cross-section of the major nonradiative recombination centers in Mg-doped GaN epilayers grown on a GaN substrate

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S. F. Chichibu, K. Shima, K. Kojima, S. Takashima, M. Edo, K. Ueno, S. Ishibashi, A. Uedono
Journal: Applied Physics Letters
Appl. Phys. Lett. 112, 211901 (2018)
https://doi.org/10.1063/1.5030645
Published: May 2018
View articletitled, Large electron capture-cross-section of the major nonradiative recombination centers in Mg-doped GaN epilayers grown on a GaN substrate
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Journal Articles

The origins and properties of intrinsic nonradiative recombination centers in wide bandgap GaN and AlGaN

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S. F. Chichibu, A. Uedono, K. Kojima, H. Ikeda, K. Fujito, S. Takashima, M. Edo, K. Ueno, S. Ishibashi
Journal: Journal of Applied Physics
J. Appl. Phys. 123, 161413 (2018)
https://doi.org/10.1063/1.5012994
Published: March 2018
View articletitled, The origins and properties of intrinsic nonradiative recombination centers in wide bandgap GaN and AlGaN
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Journal Articles

Controlling the carrier lifetime of nearly threading-dislocation-free ZnO homoepitaxial films by 3d transition-metal doping

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S. F. Chichibu, K. Kojima, Y. Yamazaki, K. Furusawa, A. Uedono
Journal: Applied Physics Letters
Appl. Phys. Lett. 108, 021904 (2016)
https://doi.org/10.1063/1.4939838
Published: January 2016
View articletitled, Controlling the carrier lifetime of nearly threading-dislocation-free ZnO homoepitaxial films by 3d transition-metal doping
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Journal Articles

Systematic investigation on in-plane anisotropy of surface and buried channel mobility of metal-oxide-semiconductor field-effect-transistors on Si-, a-, and m-face 4H-SiC

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K. Ariyoshi, R. Iijima, S. Harada, K. Kojima, J. Senzaki, Y. Tanaka, K. Takao, T. Shinohe
Journal: Applied Physics Letters
Appl. Phys. Lett. 106, 103506 (2015)
https://doi.org/10.1063/1.4914385
Published: March 2015
View articletitled, Systematic investigation on in-plane anisotropy of surface and buried channel mobility of metal-oxide-semiconductor field-effect-transistors on Si-, a-, and m-face 4H-SiC
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Journal Articles

Enhancement of crystal homogeneity of protein crystals under application of an external alternating current electric field

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H. Koizumi, S. Uda, K. Fujiwara, M. Tachibana, K. Kojima, J. Nozawa
Journal: AIP Conference Proceedings
AIP Conf. Proc. 1618, 265–268 (2014)
https://doi.org/10.1063/1.4897724
Published: October 2014
View articletitled, Enhancement of crystal homogeneity of protein crystals under application of an external alternating current electric field
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Journal Articles

Breakdown voltage in silicon carbide metal-oxide-semiconductor devices induced by ion beams

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T. Ohshima, M. Deki, T. Makino, N. Iwamoto, S. Onoda, T. Hirao, K. Kojima, T. Tomita, S. Matsuo, S. Hashimoto
Journal: AIP Conference Proceedings
AIP Conf. Proc. 1525, 654–658 (2013)
https://doi.org/10.1063/1.4802408
Published: April 2013
View articletitled, Breakdown voltage in silicon carbide metal-oxide-semiconductor devices induced by ion beams
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Journal Articles

Defect-induced performance degradation of 4H-SiC Schottky barrier diode particle detectors

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N. Iwamoto, B. C. Johnson, N. Hoshino, M. Ito, H. Tsuchida, K. Kojima, T. Ohshima
Journal: Journal of Applied Physics
J. Appl. Phys. 113, 143714 (2013)
https://doi.org/10.1063/1.4801797
Published: April 2013
View articletitled, Defect-induced performance degradation of 4H-SiC Schottky barrier diode particle detectors
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Journal Articles

E1/E2 traps in 6H-SiC studied with Laplace deep level transient spectroscopy

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A. Koizumi, V. P. Markevich, N. Iwamoto, S. Sasaki, T. Ohshima, K. Kojima, T. Kimoto, K. Uchida, S. Nozaki, B. Hamilton, A. R. Peaker
Journal: Applied Physics Letters
Appl. Phys. Lett. 102, 032104 (2013)
https://doi.org/10.1063/1.4788814
Published: January 2013
View articletitled, E1/E2 traps in 6H-SiC studied with Laplace deep level transient spectroscopy
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Journal Articles

Accurate alignment of a photonic crystal nanocavity with an embedded quantum dot based on optical microscopic photoluminescence imaging

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T. Kojima, K. Kojima, T. Asano, S. Noda
Journal: Applied Physics Letters
Appl. Phys. Lett. 102, 011110 (2013)
https://doi.org/10.1063/1.4773882
Published: January 2013
View articletitled, Accurate alignment of a photonic crystal nanocavity with an embedded quantum dot based on optical microscopic photoluminescence imaging
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Journal Articles

Strongest Pulsed Muon Source at J‐PARC MUSE

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Y. Miyake, K. Shimomura, N. Kawamura, P. Strasser, A. Koda, H. Fujimori, S. Makimura, K. Nakahara, M. Kato, S. Takeshita, K. Nishiyama, Y. Kobayashi, K. Kojima, R. Kadono, W. Higemoto, T. Ito, K. Ninomiya, M. Hiraishi, M. Miyazaki, K. Kubo
Journal: AIP Conference Proceedings
AIP Conf. Proc. 1382, 217–219 (2011)
https://doi.org/10.1063/1.3644316
Published: October 2011
View articletitled, Strongest Pulsed Muon Source at J‐PARC MUSE
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