教員・研究者詳細 - 梅津　郁朗

We collided silicon and germanium laser-induced plumes in helium background gas to clarify the behavior of the plumes after the collision. The expansion of the silicon and germanium species in the mixed plume after the collision was observed separately by spectroscopic measurements and the degree of mixing was evaluated by the experimental results. When the pressure of the background gas was 2000 Pa, the plumes moved backward after the collision with the counter-propagating shock wave, and no mixing of the plumes was observed. The effect of the counter-propagating shock wave was discussed by comparing with the results of numerical calculations based on the compressible Euler equations. At 300 Pa, the plumes concentrated at about 1 mm around the central region just after the collision and almost 100% mixing occurred in this region. The concentration and mixing of the plumes in the central region is a key to forming well-mixed plume. Stagnation and partial mixing of the plumes were observed at intermediate pressures. By decreasing the background helium gas pressure from 2000 to 300 Pa, the degree of mixing increased from 0 to about 100%. The results are compared with those in argon background gas to discuss effects of mean free path. The effects of counter-propagating shock wave, mean free path and the onset time of the collision on the backward movement and mixing of the plumes are discussed.

DOI： https://doi.org/10.1007/s00339-022-06136-1

リアルタイムオンライン指導により学生自身が自宅で行う実験・実習査読あり

市田正夫, 青木珠緖, 秋宗秀俊, 梅津郁朗

物理教育 69 ( 4 ) 257 - 264 2021年

担当区分：最終著者

学生実験の作業化への懸念と対応査読あり

梅津郁朗、青木珠緖、市田正夫、山﨑篤志、山本常夏

物理教育 68 268 - 272 2020年12月

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Expansion of laser-induced plume after the passage of a counter shock wave through a background gas 査読あり

Akira Higo, Keita Katayama, Hiroshi Fukuoka , akehito Yoshida, Tamao Aoki, Minoru Yaga, Ikurou Umezu

Applied Physics A 126 ( 4 ) 2020年3月

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担当区分：最終著者,　責任著者

DOI： 10.1007/s00339-020-03476-8

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その他リンク： http://link.springer.com/article/10.1007/s00339-020-03476-8/fulltext.html

Effect of counter shock wave on the expanding plume 査読あり

Katayama Keita, Horai Yuki, Fukuoka Hiroshi, Kinoshita Toshiki, Yoshida Takehito, Aoki Tamao, Umezu Ikurou

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 124 ( 2 ) 2018年2月

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担当区分：最終著者,　責任著者

DOI： 10.1007/s00339-018-1577-6

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Numerical analysis of behavior on opposing unsteady supersonic jets in a flow field with shields 査読あり

Toshiki Kinoshita, Hiroshi Fukuoka, Ikurou Umezu

Materials Science Forum 910 96 - 101 2018年1月

共著

担当区分：最終著者

© 2018 Trans Tech Publications, Switzerland. Collision dynamics of opposing unsteady supersonic jets injected in background gas with shock waves were calculated to simulate double pulsed laser ablation. Since the jets are deflected by collision and the motion of debris is ballistic. This characteristic can be used to reduce the number of debris when shields are mounted in front of substrate. The flow of jets through installed shields is complicated by the interaction between shields and jets, and between shields and shock waves. We investigate influence of shield position on the shock waves and the jets by numerical calculations. Axisymmetric two-dimensional compressible Euler equations were solved using the finite volume method by using ANSYS Fluent 14.0.0 code. The shields with slit was mounted parallel to the direction of initially injected jets. In order to investigate the influence of shield position on the shock waves and the jets, the shield position and background gas pressure were adopted as parameters. The jets and shock wave are deflected by collision and they can pass through the slit of shields. The passed shock wave reflects at the substrate mounted behind the slits and it forces back the jet to decrease the jet velocity. The shield position governs the velocity and amount of the jet that reach the substrate.

DOI： 10.4028/www.scientific.net/msf.910.96

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Lasing in organic mixed-crystal thin films with cavities composed of naturally formed cracks 査読あり

Mantoku Masaaki, Ichida Masao, Umezu Ikurou, Sugimura Akira, Aoki-Matsumoto Tamao

OPTICS LETTERS 42 ( 8 ) 1528 - 1531 2017年4月

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DOI： 10.1364/OL.42.001528

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e-beam irradiation effects on IR absorption bands in single-walled carbon nanotubes 査読あり

Ichida Masao, Nagao Katsunori, Ikemoto Yuka, Okazaki Toshiya, Miyata Yasumitsu, Kawakami Akira, Kataura Hiromichi, Umezu Ikurou, Ando Hiroaki

SOLID STATE COMMUNICATIONS 250 119 - 122 2017年1月

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DOI： 10.1016/j.ssc.2016.11.023

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Hierarchical Structure of TiO2 Nano-Aggregates Prepared by Pulsed Laser Ablation in Background Gas 査読あり

Umezu Ikurou, Yoshida Takehito

ELECTRONICS AND COMMUNICATIONS IN JAPAN 99 ( 10 ) 40 - 45 2016年10月

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DOI： 10.1002/ecj.11871

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Pulsed-laser-deposited TiO2 nanocrystalline films supporting Au nanoparticles for visible-light-operating plasmonic photocatalysts

Yoshida Takehito, Watanabe Tei, Kikuchi Fumito, Tabuchi Takeru, Umezu Ikurou, Haraguchi Masanobu

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 122 ( 5 ) 2016年5月

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DOI： 10.1007/s00339-016-0035-6

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Dynamics of colliding laser ablation plumes in background gas 査読あり

Umezu Ikurou, Hashiguchi Yusuke, Fukuoka Hiroshi, Sakamoto Naomichi, Aoki Tamao, Sugimura Akira

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 122 ( 4 ) 2016年4月

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DOI： 10.1007/s00339-016-9993-y

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Pulsed-laser-deposited TiO2 nanocrystalline films supporting Au nanoparticles for visible-light-operating plasmonic photocatalysts 査読あり

Yoshida, T., Watanabe, T., Kikuchi, F., Tabuchi, T., Haraguchi, M.

Applied Physics A 122 ( 5 ) 37 2016年

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Pulsed laser irradiation-induced microstructures in the Mn ion implanted Si 査読あり

Naito Muneyuki, Yamada Ryo, Machida Nobuya, Koshiba Yusuke, Sugimura Akira, Aoki Tamao, Umezu Ikurou

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS 365 110 - 113 2015年12月

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DOI： 10.1016/j.nimb.2015.07.073

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Crossover from Efros-Shklovskii variable range hopping to nearest-neighbor hopping in silicon nanocrystal random network 査読あり

Inada Mitsuru, Yamamoto Hiroshi, Gibo Manabu, Ueda Rieko, Umezu Ikurou, Tanaka Shukichi, Saitoh Tadashi, Sugimura Akira

APPLIED PHYSICS EXPRESS 8 ( 10 ) 2015年10月

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DOI： 10.7567/APEX.8.105001

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Correlation between crystallinity and mid-infrared optical absorption spectra of silicon supersaturated with sulfur 査読あり

Katsuki Nagao, Tatsuya Nakai, Muneyuki Naito, Mitsuru Inada, Tadashi Saitoh, Tamao Aoki and Akira Sugimura

MRS Proceedings 1738 mrsf14–1738–v14–05 2015年

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担当区分：筆頭著者

ガス中パルスレーザアブレーションで作製された TiO2 ナノ粒子凝集体の階層構造査読あり

吉田岳人

電気学会論文誌 C(電子・情報・システム部門誌) 135 ( 9 ) 1055 2015年

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担当区分：筆頭著者

Hyperdoping of silicon with deep-level impurities by pulsed YAG laser melting

Umezu Ikurou, Naito Muneyuki, Kawabe Daisuke, Koshiba Yusuke, Nagao Katsuki, Sugimura Akira, Aoki Tamao, Inada Mitsuru, Saitoh Tadashi, Kohno Atsushi

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 117 ( 1 ) 155 - 159 2014年10月

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DOI： 10.1007/s00339-014-8313-7

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Structural properties of TiO2 nanocrystallites condensed in vapor-phase for photocatalyst applications

Yoshida Takehito, Yagi Nobuyasu, Nakagou Riki, Sugimura Akira, Umezu Ikurou

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 117 ( 1 ) 223 - 227 2014年10月

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DOI： 10.1007/s00339-014-8378-3

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Hyperdoping of silicon with deep-level impurities by pulsed YAG laser melting. 査読あり

Naito, M., Kawabe, D., Koshiba, Y., Nagao, K., Sugimura, A., Aoki, T., Inada, M., Saitoh, T., & Kohno, A

Applied Physics A 117 155 - 159 2014年

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担当区分：筆頭著者

Hyperdoping of silicon with deep-level impurities by pulsed YAG laser melting 査読あり

Naito, M., Kawabe, D., Koshiba, Y., Nagao, K., Sugimura, A., Aoki, T., Inada, M., Saitoh, T., & Kohno, A

Applied Physics A 117 155 - 159 2014年

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Structural properties of TiO2 nanocrystallites condensed in vapor-phase for photocatalyst applications. 査読あり

Yoshida, T., Yagi, N., Nakagou, R., Sugimura, A.

Applied Physics A 117 223 - 227 2014年

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Emergence of very broad infrared absorption band by hyperdoping of silicon with chalcogens

Umezu Ikurou, Warrender Jeffrey M., Charnvanichborikarn Supakit, Kohno Atsushi, Williams James S., Tabbal Malek, Papazoglou Dimitris G., Zhang Xi-Cheng, Aziz Michael J.

JOURNAL OF APPLIED PHYSICS 113 ( 21 ) 2013年6月

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DOI： 10.1063/1.4804935

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Effects of collision between two plumes on plume expansion dynamics during pulsed laser ablation in background gas

Umezu Ikurou, Sakamoto Naomichi, Fukuoka Hiroshi, Yokoyama Yasuhiro, Nobuzawa Koichiro, Sugimura Akira

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 110 ( 3 ) 629 - 632 2013年3月

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DOI： 10.1007/s00339-012-7141-x

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Growth Processes of Porous TiO2 Nanocrystal-films during Pulsed Laser Ablation. 査読あり

I., Yagi, N., Sugimura, A., & Yoshida, T.

MRS Proceedings 1497 mrsf12–1497–k03–20 2013年

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担当区分：筆頭著者

Fluid simulation of plume head-on collision dynamics during pulsed laser ablation 査読あり

Fujii, R., Doi, K., Yokoyama, Y., Fukuoka, H., Sugimura, A., Tominaga, N

J. Phys.: Conf. Ser. 454 012009 2013年

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Emergence of very broad infrared absorption band by hyperdoping of silicon with chalcogens 査読あり

I., Warrender, J. M., Charnvanichborikarn, S., Kohno, A., Williams, J. S., Tabbal, M., Papazoglou, D. G., Zhang, X.-C., & Aziz, M. J.

Journal of Applied Physics, 113 ( 21 ) 213501 2013年

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担当区分：筆頭著者

Fluid simulation of plume head-on collision dynamics during pulsed laser ablation

梅津　郁朗

24TH IUPAP CONFERENCE ON COMPUTATIONAL PHYSICS (IUPAP-CCP 2012) 454 2013年

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DOI： 10.1088/1742-6596/454/1/012009

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Hierarchical Pattern Structure in TiO2 Nano-Aggregates Prepared by Pulsed Laser Ablation in Background Gas

梅津　郁朗

2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS PACIFIC RIM (CLEO-PR) 2013年

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DOI： 10.1109/CLEOPR.2013.6600109

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パルスレーザーメルティング法によって深い準位をとる不純物を過飽和ドープしたシリコンの赤外光吸収

梅津郁朗, 香野淳, 川邊大介, 松田祐樹, 中川将, and 杉村陽

電気学会研究会資料　光・量子デバイス研究会 QD12 47 - 50 2012年3月

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担当区分：筆頭著者

Low Temperature Bonding of Metals by Deposition of Nanoparticles at the Interface 査読あり

Toshio Takiya, Naoaki Fukuda, Ikurou Umezu, Akira Sugimura, Shigeo Ueguri, Hisao Yoshida, and Min Han

Applied Physics Research 4 42 - 47 2012年2月

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Effects of collision between two plumes on plume expansion dynamics during pulsed laser ablation in background gas 査読あり

Sakamoto, N., Fukuoka, H., Yokoyama, Y., Nobuzawa, K., & Sugimura, A

Appl Phys A 110 ( 3 ) 629 - 632 2012年

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担当区分：筆頭著者

Effects of collision between two plumes on plume expansion dynamics during pulsed laser ablation in background gas 査読あり

Sakamoto, N., Fukuoka, H., Yokoyama, Y., Nobuzawa, K., & Sugimura, A

Appl. Phys. A 110 ( 3 ) 629 - 632 2012年

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担当区分：筆頭著者

Supersaturated doping of silicon with titanium by pulsed laser melting method

Daisuke Kawabel, Shou Nakagawa, Yuuki Matsudal, Akira Sugimura, and Ikurou Umezu

Mem. Konan Univ., Sci. & Eng. Ser. 58 ( 1 ) 21 - 32 2011年12月

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Synthesis of GaN nanocrystallites by pulsed laser ablation in pure nitrogen background gases 査読あり

T Yoshida, S. Kakumoto, A Sugimura, and I Umezu

Applied Physics A: Materials Science & Processing 104 907 - 911 2011年9月

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Photoluminescence from Excited Energy Bands in Au-25 Nanoclusters

Sakanaga Isamu, Inada Mitsuru, Saitoh Tadashi, Kawasaki Hideya, Iwasaki Yasuhiko, Yamada Toshiki, Umezu Ikurou, Sugimura Akira

APPLIED PHYSICS EXPRESS 4 ( 9 ) 2011年9月

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DOI： 10.1143/APEX.4.095001

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Synthesis of GaN nanocrystallites by pulsed laser ablation in pure nitrogen background gases

Yoshida Takehito, Kakumoto Soichiro, Sugimura Akira, Umezu Ikurou

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 104 ( 3 ) 907 - 911 2011年9月

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DOI： 10.1007/s00339-011-6438-5

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Photoluminescence from Excited Energy Bands in Au$_{25}$ Nanoclusters 査読あり

Isamu Sakanaga, Mitsuru Inada, Tadashi Saitoh, Hideya Kawasaki, Yasuhiko Iwasaki, Toshiki Yamada, Ikurou Umezu, and Akira Sugimura

Appl. Phys. Express 4 095001-1 - 095001-3 2011年8月

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Strong mid-infrared optical absorption emerged by supersaturated sulfur doping in silicon wafer 査読あり

I. Umezu, A. Kohno, J. M. Warrender, Y. Takatori, Y.Hirao, S. Nakagawa, A. Sugimura, S. Charnvanichborikarn, J. S. Williams and M. J. Aziz

Proceedings of 30th International Conference on the Physics of Semiconductors 1399 51 - 52 2011年1月

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Effect of Non-equilibrium Pulsed Ejection of Si Species into Background Gas on the Formation of Si Nanocrystallite 査読あり

Ikurou Umezu, Shunto Okubo , Akira Sugimura

Mater. Res. Soc. Symp. Proc. 1035 2011年1月

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担当区分：筆頭著者

Development of precise tuning method of inter-dot spacing and resonant energy transfer between Au clusters

Inada Mitsuru, Yoshihara Yoshihiro, Kawasaki Hideya, Iwasaki Yasuhiko, Saitoh Tadashi, Umezu Ikurou, Sugimura Akira

NANOPHOTONIC MATERIALS VIII 8094 2011年

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DOI： 10.1117/12.893716

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Roles of SiH4 in Growth, Structural Changes and Optical Properties Of Nanocrystalline Silicon Thin Films

Ali A. M., Inokuma T., Al-Hajry A., Kobayashi H., Umezu I., Morimoto A.

PROCEEDINGS OF THE FIFTH SAUDI PHYSICAL SOCIETY CONFERENCE (SPS5) 1370 2011年

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DOI： 10.1063/1.3638084

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Strong mid-infrared optical absorption by supersaturated sulfur doping in silicon

Umezu I., Kohno A., Warrender J. M., Takatori Y., Hirao Y., Nakagawa S., Sugimura A., Charnvanichborikarn S., Williams J. S., Aziz M. J.

PHYSICS OF SEMICONDUCTORS: 30TH INTERNATIONAL CONFERENCE ON THE PHYSICS OF SEMICONDUCTORS 1399 2011年

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DOI： 10.1063/1.3666252

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Effect of non-equilibrium pulsed ejection of Si species into background gas on the formation of Si nanocrystallite and nanocrystal-film

Ikurou Umezu, Shunto Okubo, Akira Sugjmura

Materials Research Society Symposium Proceedings 1305 13 - 18 2011年

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The Si nanocrystal-films are prepared by pulsed laser ablation of Si target in a mixture of helium and hydrogen gas. The total gas pressure and hydrogen partial gas pressure were varied to control structure of nanocrystal-film. The surface of Si nanocrystallite was hydrogenated and degree of hydrogenation increased with increasing hydrogen partial gas pressure. The aggregate structure of nanocrystal-film depended on both the total gas pressure and the hydrogen partial gas pressure. The former and the latter alter spatial confinement of Si species during deposition and the surface hydrogenation of individual nanocrystal, respectively. Spatial confinement increases probability of collision between nanocrystals in the plume. While, surface hydrogenation prevents coalescence of nanocrystals. The individual or aggregated nanocrystals formed in the plume reach the substrate and the nanocrystal-film is deposited on the substrate. The non-equilibrium growth processes duringpulsed laser ablation are essential for the formation of the surface structure and the subsequent nanocrystal-film growth. Our results indicate that the structure of nanocrystal-film depends on the probabilities of collision and coalescence between nanocrystals in the plume. These probabilities can be varied by controlling the total gas pressure and the hydrogen partial gas pressure. © 2011 Materials Research Society.

DOI： 10.1557/opl.2011.87

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ガス中パルスレーザアブレーションでのSiナノ構造の生成過程に対するパルス励起の効果

梅津郁朗

レーザ加工学会誌 17 93 2010年11月

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担当区分：筆頭著者

Emission induced by collision of two plumes during pulsed laser ablation 査読あり

I. Umezu, S. Yamamoto and A. Sugimura

Applied Physics A: Materials Science & Processing 101 133 - 136 2010年11月

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担当区分：筆頭著者

Formation of core-shell structured silicon nanoparticles during pulsed laser Ablation 査読あり

I. Umezu, Y. Nakayama and A. Sugimura

J. Appl. Phys. 2010年11月

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Inter-Dot Distance Dependence of Photoluminescence Properties in CdSe Quantum Dot Systems

K. Tai, W. Lü, I. Umezu and A. Sugimura

Appl. Phys. Express 3 035202 2010年11月

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担当区分：筆頭著者

Fabrication and Sub-Bandgap Optical Properties of Silicon Supersaturated with Chalcogens by Ion Implantation and Pulsed Laser Melting 査読あり

Fabrication and Sub-Bandgap Optical Properties of Silicon Supersaturated with Chalcogens by Ion Implantation and Pulsed Laser Melting

B. P. Bob, A. Kohno, S. Charnvanichborikarn, J. M. Warrender, I. Umezu, M. Tabbal, J. S. Williams and M. J. Aziz 107 123506 2010年11月

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Emission induced by collision of two plumes during pulsed laser ablation

Umezu Ikurou, Yamamoto Shigeki, Sugimura Akira

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 101 ( 1 ) 133 - 136 2010年10月

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DOI： 10.1007/s00339-010-5772-3

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Fabrication and subband gap optical properties of silicon supersaturated with chalcogens by ion implantation and pulsed laser melting

Bob Brion P., Kohno Atsushi, Charnvanichborikarn Supakit, Warrender Jeffrey M., Umezu Ikurou, Tabbal Malek, Williams James S., Aziz Michael J.

JOURNAL OF APPLIED PHYSICS 107 ( 12 ) 2010年6月

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DOI： 10.1063/1.3415544

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Formation of core-shell structured silicon nanoparticles during pulsed laser ablation

Umezu Ikurou, Nakayama Yusuke, Sugimura Akira

JOURNAL OF APPLIED PHYSICS 107 ( 9 ) 2010年5月

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DOI： 10.1063/1.3374660

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Inter-Dot Distance Dependence of Photoluminescence Properties in CdSe Quantum Dot Systems

Tai Kohei, Lue Wei, Umezu Ikurou, Sugimura Akira

APPLIED PHYSICS EXPRESS 3 ( 3 ) 2010年

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DOI： 10.1143/APEX.3.035202

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Synthesis of Ni-doped InTaO4 nanocrystallites by reactive pulsed laser ablation for application to visible-light-operating photocatalysts 査読あり

Takehito Yoshida, Hirokazu Toyoyama, I Umezu, Akira Sugimura

Applied surface science 255 9634 - 9637 2009年11月

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Trap state emission of water-soluble CdS nanocrystals 査読あり

W Lü, Y Tokuhiro, I Umezu, A Sugimura, Y Nagasaki

phys. stat. sol. (c) 6 346 - 349 2009年11月

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Synthesis of Ni-doped InTaO4 nanocrystallites by reactive pulsed laser ablation for application to visible-light-operating photocatalysts

Yoshida Takehito, Toyoyama Hirokazu, Umezu Ikurou, Sugimura Akira

APPLIED SURFACE SCIENCE 255 ( 24 ) 9634 - 9637 2009年9月

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DOI： 10.1016/j.apsusc.2009.04.124

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Fluorescence Resonance Energy Transfer and Concentration Quenching Effect in CdSe Quantum Dot System

Kohei Tai, Wei Lu, Ikurou Umezu, A Sugimura

Mem. konan Univ. , Sci. &Eng Ser. 56 11 2009年4月

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Effect of Phosphorus Ion Doping for Silicon Nanocrystal Assembly

Kei Hirata, Manabu Gibo, Kenichi Yoshida, Mitsuru Inuda, Ikurou Umezu, Shinji Nagamachi, Tadashi Saitoh, Akira Sugimura

Mem. konan Univ. , Sci. & Eng Ser. 56 2009年4月

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Simulation of effect of pulse width on super saturated doping by pulsed laser melting method

Shou Nakagawa, Ikurou Umezu, Akira Sugimura

Mem. konan Univ. , Sci. & Eng Ser. 56 1 2009年4月

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Trap state emission of water-soluble CdS nanocrystals

W. Lü, Y. Tokuhiro, I. Umezu, A. Sugimura, Y. Nagasaki

Physica Status Solidi (C) Current Topics in Solid State Physics 6 ( 1 ) 346 - 349 2009年

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We prepared water-soluble CdS nanocrystals (NCs) capped by the poly (ethylene glycol)b-poly (2-(N,N-dimethylammojethyl methacrylate) chain. The photoluminescence (PL) properties of CdS NCs are investigated by time-resolved and temperature-dependent PL spectra. It IB found that the PL band of CdS NCs is dominated by two trap state emissions, respectively. Due to the trap state emissions, fluorescent resonance energy transfer from CdS NCs to organic dyes (Texasred) can be observed, which suggests the potential application of trap states of CdS NCs for fabrication of biosensors. © 2009 WILEY-VCH Verlag GmbH &amp
Co. KGaA.

DOI： 10.1002/pssc.200879866

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InTaO4-based nanostructures synthesized by reactive pulsed laser ablation

Yoshida Takehito, Toyoyama Hirokazu, Umezu Ikurou, Sugimura Akira

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 93 ( 4 ) 961 - 966 2008年12月

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DOI： 10.1007/s00339-008-4760-3

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Oxidation processes of surface hydrogenated silicon nanocrystallites prepared by pulsed laser ablation and their effects on the photoluminescence wavelength （共著）

I. Umezu, A. Sugimura, T. Makino, M. Inada and K. Matsumoto

J. Appl. Phys. 2008年11月

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担当区分：筆頭著者

J. Appl. Phys. 103, (2008) 024305

Collective Transport in Silicon Nanocrystal Assembly Prepared by Laser Ablation Method 査読あり

Akira Sugimura, Manabu Gibo, Mitsuru Inada, Tadashi Saitoh, I Umezu

Mater. Res. Soc. Symp. Proc. 1145 2008年11月

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Formation of surface stabilized Si nanocrystal by pulsed laser ablation in hydrogen gas 査読あり

Ikurou Umezu, Issei Kondo, Akira Sugimura

Applied Physics A 93 717 - 720 2008年11月

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InTaO4-based nanostructures synthesized by reactive pulsed laser ablation 査読あり

Takehito Yoshida, Hirokazu Toyoyama, Ikurou Umezu, Akira Sugimura

Applied Physics A 93 961 - 966 2008年11月

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Surface hydrogenation of silicon nanocrystallites during pulsed laser ablation of silicon target in hydrogen background gas 査読あり

Ikurou Umezu, Masatoshi Takata, Akira Sugimura

J. Appl. Phys 103 11309 2008年11月

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担当区分：筆頭著者

Evolution of Energy Transfer Process between Quantum Dots of Two Different Sizes during the Evaporation of Solvent 査読あり

W. Lu, I Umezu, A Sugimura

Japanese Journal of Applied Physics 47 6592 - 6595 2008年11月

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Oxidation processes of surface hydrogenated silicon nanocrystallites prepared by pulsed laser ablation and their effects on the photoluminescence wavelength 査読あり

Ikurou Umezu, Toshiharu Makino, Mitsuru Inada, Kimihisa Matsumoto, Akira Sugimura

Journal of Applied Physics 103 024305 2008年11月

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担当区分：筆頭著者

Interfacial strain effects on optical response of CdSe/ZnS core/shell quantum dots

W Lu, I Umezu, A Sugimura

Mem.Konan Unive.Sci&Eng 53 153 - 161 2008年11月

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Collective transport in silicon nanocrystal assembly 査読あり

Manabu Gibo, Mitsuru Inada, Tadashi Saitoh, Ikurou Umezu, Akira Sugimura

Proceedings of The International Meeting for Future of Electron Devices 2008 115 - 116 2008年11月

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Direct observation of resonance energy transfer between two different sized quantum dots 査読あり

W Lü, I Umezu, A Sugimura

Proceeding of the 2nd Thailand Nanotechnology Conference 2008年11月

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Formation of surface stabilized Si nanocrystal by pulsed laser ablation in hydrogen gas

Umezu Ikurou, Kondo Issei, Sugimura Akira

APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 93 ( 3 ) 717 - 720 2008年11月

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DOI： 10.1007/s00339-008-4719-4

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Evolution of Energy Transfer Process between Quantum Dots of Two Different Sizes during the Evaporation of Solvent

Lue Wei, Umezu Ikurou, Sugimura Akira

JAPANESE JOURNAL OF APPLIED PHYSICS 47 ( 8 ) 6592 - 6595 2008年8月

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DOI： 10.1143/JJAP.47.6592

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Surface hydrogenation of silicon nanocrystallites during pulsed laser ablation of silicon target in hydrogen background gas

Umezu Ikurou, Takata Masatoshi, Sugimura Akira

JOURNAL OF APPLIED PHYSICS 103 ( 11 ) 2008年6月

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DOI： 10.1063/1.2938051

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Oxidation processes of surface hydrogenated silicon nanocrystallites prepared by pulsed laser ablation and their effects on the photoluminescence wavelength

Umezu Ikurou, Sugimura Akira, Makino Toshiharu, Inada Mitsuru, Matsumoto Kimihisa

JOURNAL OF APPLIED PHYSICS 103 ( 2 ) 2008年1月

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DOI： 10.1063/1.2832392

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Study of energy transfer in mixed system of two different sized quantum dots

Wei Lü, I Umezu, Akira Sugimura

Trends in NanoTechnology- TNT2007 2007年11月

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Mechanism of Electron-Hole Pair Generation and Light Emission for Electro-Luminescence Devices with Silicon Nano-Crystals Prepared by Laser Ablation Method

Sugimura and Koyama and Inada and Yoshida and Umezu

Proceedings of 28th international conference on the physics of semiconductors 2007年11月

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Excitation energy transfer based on trap states of CdS quantum dots 査読あり

Wei Lü, Ikurou Umezu, Akira Sugimura

Nanoinsight 2007 international conference 2007年11月

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Synthesis of photoluminescent colloidal silicon nanoparticles by pulsed laser ablation in liquids 査読あり

I Umezu, H Minami, H Senoo, A Sugimura

Journal of Physics: Conference Series 59 2007年11月

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担当区分：筆頭著者

Fractal growth of silicon nanocrystallites during pulsed laser ablation 査読あり

I Umezu, M Inada, T Makino, A Sugimura

Proceedings of 28th international conference on the physics of semiconductors 2007年11月

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担当区分：筆頭著者

Formation of nanoscale fine-structured silicon by pulsed laser ablation in hydrogen background gas 査読あり

Ikurou Umezu, Akira Sugimura, Mitsuru Inada, Toshiharu Makino, Kimihisa Matsumoto, Masatoshi Takata

Phys. Rev. B 76 045328 2007年11月

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Plume analysis during pulsed laser ablation of silicon in hydrogen gas 査読あり

M Takata, I Umezu, A Sugimura

J. Phys.: Conf. Ser. 59 575 - 578 2007年11月

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Effects of surface oxidation on optical absorption of sillicon nanocrystallites 査読あり

Umezu and Koyama and Yoshida and Sugimura

Proceedings of 28th international conference on the physics of semiconductors 2007年11月

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Nanoparticle formation in the expansion process of a laser ablated plume

M Takiya, I Umezu, M Yaga, M Han

J. Phys.: Conf. Ser. 59 445 - 448 2007年11月

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Electron transport in hydrogen-passivated silicon nanochains prepared by pulsed laser ablation

H Yamamoto, M Inada, R Ueda, I Umezu, S tanaka, T Saitoh, A Sugimura

Mem. konan Univ. , Sci. Ser. 54 89 - 103 2007年11月

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Interaction effect among silicon nanocrystallites caused by aggregation structure

I Kondo, I Umezu, A Sugimura

Mem. konan Univ. , Sci. Ser. 54 105 - 117 2007年11月

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Formation of nanoscale fine-structured silicon by pulsed laser ablation in hydrogen background gas

Umezu Ikurou, Sugimura Akira, Inada Mitsuru, Makino Toshiharu, Matsumoto Kimihisa, Takata Masatoshi

PHYSICAL REVIEW B 76 ( 4 ) 2007年7月

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DOI： 10.1103/PhysRevB.76.045328

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Effect of surface oxidation on optical absorption of silicon nanocrystallites

Umezu Ikurou, Koyama Motohiko, Yoshida Takehito, Sugimura Akira

PHYSICS OF SEMICONDUCTORS, PTS A AND B 893 895 - + 2007年

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DOI： 10.1063/1.2730180

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Fractal growth of silicon nanocrystaffites during pulsed laser ablation

Umezu Ikurou, Inada Masuru, Makino Toshiharu, Sugimura Akira

PHYSICS OF SEMICONDUCTORS, PTS A AND B 893 43 - + 2007年

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DOI： 10.1063/1.2729761

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Synthesis of photoluminescent colloidal silicon nanoparticles by pulsed laser ablation in liquids

Umezu I., Minami H., Senoo H., Sugimura A.

COLA'05: 8TH INTERNATIONAL CONFERENCE ON LASER ABLATION 59 392 - + 2007年

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DOI： 10.1088/1742-6596/59/1/083

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Plume analysis during pulsed laser ablation of sillicon in hydrogen gas

Takata M., Umezu I., Sugimura A.

COLA'05: 8TH INTERNATIONAL CONFERENCE ON LASER ABLATION 59 575 - + 2007年

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DOI： 10.1088/1742-6596/59/1/123

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Nanoparticle formation in the expansion process of a laser ablated plume

Takiya T., Umezu I., Yaga M., Han M.

COLA'05: 8TH INTERNATIONAL CONFERENCE ON LASER ABLATION 59 445 - + 2007年

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DOI： 10.1088/1742-6596/59/1/095

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Mechanism of electron-hole pair generation and light emission for electro-luminescence devices with silicon nano-crystals prepared by laser ablation method

Sugimura A., Koyama M., Inada M., Yoshida T., Umezu I.

PHYSICS OF SEMICONDUCTORS, PTS A AND B 893 1433 - + 2007年

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DOI： 10.1063/1.2730444

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Resonance energy transfer based on shallow and deep energy levels of biotin-po lyethylene glycol/polyamine stabilized CdS quantum dots.（共著）

W. Lu; , Y. Tokuhiro, I. Umezu and A. Sugimura, Y. Nagasaki.

Applied Physics Letters, 89 ( 143901 ) 1 - 3 2006年11月

共著

Applied Physics Letters, Vol.89, 143901, pp.1-3. (2006)

Size-dependent optical properties of CdSe/ZnS core/shell quantum dots

W Lü, I Umezu, A Sugimura

Mem. Konan Univ., Sci. & Eng. Ser. 53 151 - 163 2006年11月

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Resonance energy transfer based on shallow and deep energy levels of biotin-polyethylene glycol/polyamine stabilized CdS quantum dots

Lu W., Tokuhiro Y., Umezu I., Sugimura A., Nagasaki Y.

APPLIED PHYSICS LETTERS 89 ( 14 ) 2006年10月

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DOI： 10.1063/1.2359295

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Effects of surface adsorption on the photoluminescence wavelength of silicon nanocrystal

Umezu I, Kimura T, Sugimura A

PHYSICA B-CONDENSED MATTER 376 853 - 856 2006年4月

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DOI： 10.1016/j.physb.2005.12.213

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Spatial fluctuation enhancement and nonradiative-recombination-center generation due to high Si-doping into GaAs/A1As short-period-superlattices

Kobori H, Shigetani A, Umezu I, Sugimura A

PHYSICA B-CONDENSED MATTER 376 861 - 863 2006年4月

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DOI： 10.1016/j.physb.2005.12.215

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Localization and transport of type-II excitons in spatially enhanced random potential for highly Si-doped GaAs/AlAs short-period-superlattices

Kobori H., Shigetani A., Umezu I., Sugimura A.

LOW TEMPERATURE PHYSICS, PTS A AND B 850 1520 - + 2006年

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DOI： 10.1063/1.2355281

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Unusual behavior on line-broadening of photoluminescence spectrum for type-II excitons in highly Si-doped GaAs/AlAs short-period-superlattices

Kobori H., Shigetani A., Umezu I., Sugimura A.

LOW TEMPERATURE PHYSICS, PTS A AND B 850 1522 - + 2006年

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DOI： 10.1063/1.2355282

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Correlation between natural oxidation process and photoluminescence properties of hydrogenated Si nanocrystallites prepared by pulsed laser ablation

Matsumoto K, Inada M, Umezu I, Sugimura A

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 44 ( 12 ) 8742 - 8746 2005年12月

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DOI： 10.1143/JJAP.44.8742

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A correlation between natural oxidation process and PL properties of hydrogenated Si nanocrystallites prepared by pulsed laser ablation. （共著）

K. Matsumoto, M. Inada, I. Umezu and A. Sugimura.

Jpn. J. Appl. Phys. 44, 8742 - 8746 2005年11月

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Correlation between PL emission band and growth of oxide layer on surface of silicon nanocrystallites（共著）

I. UMEZU, M. Koyama, T. Hasegawa, K. Matsumoto, M. Inada and A. Sugimura.

AIP conference proceedings (The Proceedings of the 27th International Conference on the Physics of Semiconductors) 772, 855 - 856 2005年11月

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担当区分：筆頭著者

Correlation between electronic structure and chemical bond on the surface of hydrogenated silicon nanocrystallites.　（共著）

I. UMEZU, T. Makino, M. Takata, M. Inada and A. Sugimura.

AIP conference proceedings (The Proceedings of the 27th International Conference on the Physics of Semiconductors) 772, . 691 - 692 2005年11月

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担当区分：筆頭著者

Preparation of surface controlled silicon nanocrystallites by pulsed laser ablation. （共著）

I. UMEZU, M. Inada, T. Makino and A. Sugimura.

AIP conference proceedings (The Proceedings of the 27th International Conference on the Physics of Semiconductors) 772,. 861 - 862 2005年11月

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担当区分：筆頭著者

Considereable enhancement of PL intensity for free exciton in ZnO 　ultra-fine-particles and oscillatory green band emergence in PL spectrum for Cu-doped ZnO ultra-fine particles with heat treatment. （共著）

H. Kobori, T. Nanao, S. Kawaguchi, I. Umezu and A. Sugimura.

The Proceedings of the 27th International Conference on the Physics of Semiconductors 867 - 868 2005年11月

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"Temperature dependence of time-resolved luminescence spectra for 1D excitons in single-walled carbon nanotubes in micelles.　（共著）

M. Ichida, I. Umezu, H. Kataura, M. Kimura, S. Suzuki, Y. Achiba and H. Ando.

Journal of Luminescence 112, 287 - 290 2005年11月

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Formation of Hydrogen-passivated silicon Nanochains by Pulsed laser Ablation without Thermal Annealing

梅津郁郎

Mater. Res. Soc. Symp. Proc. 832, (2005)F7.24.1-F7.24.5. 2005年11月

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Structual and optical properties of surface-hydrogeneted　silicon nanocrystallites prepeared by reactive pulsed laser ablation.（共著）

T.Makino,M.Inada,Umezu and A.Sugimura.

J. Phys. D 38, 3507 - 3511 2005年11月

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Structural and optical properties of surface-hydrogenated silicon nanocrystallites prepared by reactive pulsed laser ablation

Makino T, Inada M, Umezu I, Sugimura A

JOURNAL OF PHYSICS D-APPLIED PHYSICS 38 ( 18 ) 3507 - 3511 2005年9月

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DOI： 10.1088/0022-3727/38/18/028

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Temperature dependence of time-resolved luminescence spectra for ID excitons in single-walled carbon nanotubes in micelles

Ichida M, Umezu I, Kataura H, Kimura M, Suzuki S, Achiba Y, Ando H

JOURNAL OF LUMINESCENCE 112 ( 1-4 ) 287 - 290 2005年4月

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DOI： 10.1016/j.jlumin.2004.09.104

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Considerable enhancement of PL intensity for free exciton in ZnO ultra-fine-particles and oscillatory green band emergence in PL spectrum for Cu-doped ZnO ultra-fine-particles with heat treatment

Kobori H, Nanao T, Kawaguchi S, Umezu I, Sugimura A

Physics of Semiconductors, Pts A and B 772 867 - 868 2005年

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DOI： 10.1063/1.1994381

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Correlation between PL emission band and growth of oxide layer on surface of silicon nanocrystallites

Umezu I, Koyama M, Hasegawa T, Matsumoto K, Inada M, Sugimura A

Physics of Semiconductors, Pts A and B 772 855 - 856 2005年

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DOI： 10.1063/1.1994375

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Correlation between electronic structure and chemical bond on the surface of hydrogenated silicon nanocrystallites

Umezu I, Makino T, Takata M, Inada M, Sugimura A

Physics of Semiconductors, Pts A and B 772 691 - 692 2005年

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DOI： 10.1063/1.1994294

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Preparation of surface controlled silicon nanocrystallites by pulsed laser ablation

Umezu I, Inada M, Makino T, Sugimura A

PHYSICS OF SEMICONDUCTORS, PTS A AND B 772 861 - 862 2005年

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DOI： 10.1063/1.1994378

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Correlation between surface oxide and photoluminescence properties of Si nanoparticles prepared by　pulsed laser ablation（共著）

I. Umezu, K. Matsumoto, M. Inada, T. Makino and A. Sugimura

Applied Physics A 79, 1545 - 1547 2004年11月

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担当区分：筆頭著者

Recombination process of CdS quantum dot covered by novel Polymer Chains（共著）

I. Umezu, R. Koizumi, A. Sugimoto, M. Inada, T. Makino, A. Sugimura, Y. Sunaga, T. Ishii and Y. Nagasaki

Physica E 21, 1102 - 1105 2004年11月

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担当区分：筆頭著者

Optical and transport studies in coupled InAs quantum dots embedded in GaAs（共著）

M. Inada, I. Umezu, P. O. Vaccaro, S. Yamada and A. Sugimura

Physica E 21, 317 - 321 2004年11月

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Inter-dot electron transport in coupled InAs quantum dots under magnetic field（共著）

M. Inada, I. Umezu, P. O. Vaccaro, S. Yamada and A. Sugimura

Semicond. Sci. Technol. 19, 54 - 55 2004年11月

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Semicond. Sci. Technol. 19, (2004)S54-S55,

Structural and optical properties of silicon nanoparticles prepared by　pulsed laser ablation in hydrogen backgrond gas（共著）

T. Makino, M. Inada1, K. Yoshida, I. Umezu and A. Sugimura1

Applied Physics A to be, 2004年11月

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Optical Properties of CdS Nanocrystal Covered by Polymer Chains on the Surface（共著）

I. Umezu, K. Mandai, R. Koizumi, M. Inada, A. Sugimura, Y. Sunaga, T. Ishii and Y. Nagasaki

MicroElectronic Engineering 66, 53 - 58 2003年11月

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Observation of inter-dot electron transport via spin-split states in InAs quantum dots （共著）

M. Inada, S. Sato, I. Umezu, P. O. Vaccaro, S. Yamada and A. Sugimura.

(Institute of Physics Publishing, Bristol (UK)and Philadelphia (USA), 2003) Institute of Physics Conference Series Number 171 、H188,1-5. 2003年11月

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Effects of hydroganation on photoluminescence of Si nanoparticles formed by pulsed laser ablation（共著）

M. Inada, H. Nakagawa, I. Umezu and A. Sugimura

Materials Science & Engineering B 101, 283 - 285 2003年11月

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Effect of gas pressure on reactive pulsed laser ablation of a silicon target（共著）

M. Inada, I. Umezu and A. Sugimura

J. Vac. Sci. Technol. A 21, 84 - 86 2003年11月

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Mechanizms of Visible Photoluminescence from Size-Controlled Silicon Nanoparticles（共著）

T. Makino, N. Suzuki, Y. Yamada, T. Yoshida, I. Umezu and A. Sugimura

Mat. Res. Soc. Symp. Proc. 737, 265 - 270 2003年11月

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Optical properties of CdS quantum dot covered by novel polymer chains（共著）

I　Umezu, K.Mandai1, R. Koizumi1, M. Inada, A. Sugimura, Y. Sunaga, T. Ishii and Y. Nagasaki.

(Institute of Physics Publishing, Bristol (UK)and Philadelphia (USA), 2003) Institute of Physics Conference Series Number 171 、H202, 1-5, 2003年11月

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担当区分：筆頭著者

Correlation between structure and nonradiative recombination process　in silicon nanocrystallites （共著）

I　Umezu, M. Inada, H. Nakagawa, K. Matsumoto and A. Sugimura.

(Institute of Physics Publishing, Bristol (UK)and Philadelphia (USA), 2003) Institute of Physics Conference Series ，Number 171 D173, 1-5, 2003年11月

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担当区分：筆頭著者

Reaction between nitrogen gas and silicon species during　pulsed laser ablation（共著）

I. Umezu, M. Inada, K. Kohno, T. Yamaguchi, T. Makino and A. Sugimura

J. Vac. Sci. Technol. A 21, 1680 - 1682 2003年11月

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担当区分：筆頭著者

Mechanisms of visible photoluminescence from size-controlled silicon nanoparticles

Makino T, Suzuki N, Yamada Y, Yoshida T, Umezu I, Sugimura A

QUANTUM CONFINED SEMICONDUCTOR NANOSTRUCTURES 737 265 - 270 2003年

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Preparation of SiNx film by pulsed laser ablation in nitrogen gas ambient（共著）

I. Umezu, T. Yamaguchi, K. Kohno, M. Inada and A. Sugimura

Appl. Surf. Sci. 197-198C, 314 - 316 2002年11月

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担当区分：筆頭著者

Deposition of silicon nitride films by pulsed laser ablation of Si target in nitrogen gas（共著）

I. Umezu, K. Kohno, T. Yamaguchi, A. Sugimura and M. Inada

J. Vac. Sci. and technol. A 20, (2002)30-32， 2002年11月

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担当区分：筆頭著者

Study of silicon nanocrystal prepared by pulsed laser ablation in H2 gas（共著）

K. Matsumoto, H. nakagawa, M. Inada, I. Umezu and A. Sugimura

Mem. Konan Univ., Sci. Ser. 49, (2002)17-23, 2002年11月

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Nano-oxidation of an amorphous silicon surface with an atomic force microscope（共著）

I. Umezu, T. Yoshida, K. Matsumoto, M. Inada and A. Sugimura

J. Noncryst. solids 299-302, (2002)1090-1094, 2002年11月

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担当区分：筆頭著者

Effects of hydrogen on Si nanoparticles formed by pulsed laser ablation（共著）

M. Inada, H. Nakagawa, I. Umezu and A. Sugimura

Applied surface science 197-198, (2002)666-669, 2002年11月

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Effect of Structure on Radiative Recombination Process in Amorphous Silicon Suboxide Prepared by RF Sputtering（共著）

K.-i. Yoshida, I. Umezu, N. Sakamoto, M. Inada and A. Sugimura

Journal of applied physics 92, 5936 - 5941 2002年11月

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Photoluminescence Properties of Amorphous Silicon-based Oxygen and Hydrogen Alloys（共著）

I. Umezu, K.-i. Yoshida, N. Sakamoto, T. Murota, Y. Takashima, M. Inada and A. Sugimura

J.Appl. Phys. 91, 2009 - 2014 2002年11月

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担当区分：筆頭著者

Effects of Argon and hydrogen plasmas on the surface of silicon（共著）

I. Umezu, K. Kohno, K. Aoki, Y. Kohama, A. Sugimura and M. Inada

Vacuum 66/3-4, 453 - 456 2002年11月

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担当区分：筆頭著者

Nanoscale anodization of an amorphous silicon surface with an atomic force microscope（共著）

I. Umezu, Takashi Yoshida, K. Matsumoto, A. Sugimura and M. Inada

Appl. Phys. Lett. 81, 1492 - 1493 2002年11月

共著

担当区分：筆頭著者

Preparation of SiNx film by pulsed laser ablation in nitrogen gas ambient（共著）

I. Umezu, T. Yamaguchi, K. Kohno, M. Inada and A. Sugimura

Appl. Surf. Sci. 197-198C, 314 - 316 2002年11月

共著

担当区分：筆頭著者

Effects of annealing on luminescence properties of si nanocrystallites prepared by pulsed laser ablation in inert gas（共著）

I. Umezu, G. Yamazaki, T. Yamaguchi, A. Sugimura, T. Makino, Y. Yamada, N. Suzuki and T. Yoshida，

Materials Science & Engineering C Vol 15/1-2, (2001)129-131， 2001年11月

共著

担当区分：筆頭著者

Many body effect in photo-conductivity in InAs/GaAs self assembled quantum dots（共著）

M. Inada, K. Ohnishi, I. Umezu, P. O. Vaccaro and A. Sugimura

Mat. Res. Soc. Symp. Proc. 642, (2001)J3.3.2-J3.3.6 2001年11月

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Effects of inter-dot electronic coupling on laser gain in InAs/GaAs quantum dot ensemble（共著）

A. Sugimura, K. Ohnishi, I. Tadamasa and I. Umezu

Mat.Res.Soc.Symp.Proc., 642, (2001)J5.5.1-J5.5.6， 2001年11月

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Conduction-type control of Ge films grown on (NH4)2S-treated GaAs by molecular beam epitaxy（共著）

M. Inada, T. Fujishima, I. Umezu, A. Sugimura and S. Yamada

Journal of Crystal Growth 227-228, (2001)791-795 2001年11月

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Photoluminescence from Nanoscale Si in a-SiOx matrix（共著）

I. Umezu, K. Yoshida, M. Inada and A. Sugimura，

Mat. Res. Soc Symp. Proc. 638, (2001)F5.19.1-F5.19.6 2001年11月

共著

担当区分：筆頭著者

Effect of Non-equilibrium Pulsed Ejection of Si Species into Background Gas on the Formation of Si Nanocrystallite and Nanocrystal-film 査読あり

Ikurou Umezu, Shunto Okubo, Akira Sugimura

Mater. Res. Soc. Symp. Proc. 1305 2001年11月

共著

担当区分：筆頭著者

DOI： 10.1557

Lateral photo-conductance via in-plane interdot tunneling in self-assembled InAs/GaAs quantum dot ensemble

Ohnishi K, Inada M, Umezu I, Sugimura A, Vaccaro PO

PROCEEDINGS OF THE 25TH INTERNATIONAL CONFERENCE ON THE PHYSICS OF SEMICONDUCTORS, PTS I AND II 87 1063 - 1064 2001年

共著

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Lateral photo-conductance via in-plane inter-dot tunneling in self-assembled InAs/GaAs quantum dot ensemble（共著）

K. Ohnishi, M. Inada, I. Umezu, A. Sugimura and P. O. Vaccaro

Proc.25th Int. Conf. Phys. Semicond 1063 - 1064 2000年11月

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correlation between Photoluminescence Intensity and Micro Structure in Amorphous Silicon Films Prepared by Reactive RF Sputtering（共著）

Umezu, T. Murota, M. Kawata, Y. Takashima, K.-i. Yoshida, M. Inada and A. Sugimura

Jpn. J. Appl. Phys. 39 Part2, (2000)L844-L846, 2000年11月

共著

担当区分：筆頭著者

Structure, optical absorption and electronic states of Zn+ ion implanted and subsequently annealed sol-gel anatase TiO2 films（共著）

K. Oyoshi, N. Sumi, I. Umezu, R. Souda, A. Yamazaki, H. Haneda and T. Mitsuhashi

Nuclear Instruments and Methods in Physics Research B 168/2, 221 - 228 2000年11月

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Microstructure in a-SiOx prepared by RF sputtering method and its effect on radiative recombination mechanism（共著）

K. Yoshida, M. Inada, I. Umezu and A. Sugimura

Mem. konan Univ. , Sci. Ser. 47　(2) 119 - 132 2000年11月

共著

Resonance Raman Scattering of Br2 Doped Single-Walled Carbon Nanotube Bundles

梅津郁郎

Mo. Cryst. and Liq. Cryst. 340, 757 - 762 2000年11月

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Journal of Non-Crystalline Solids 266-9（共著）

H. Kataura, Y. Kumazawa, N. Kojima, Y. Maniwa, I. Umezu, S. Masubuchi, S. Kazama, Y. Ohtsuka, S. Suzuki and Y. Achiba

Journal of Non-Crystalline Solids 266-9, 1029 - 1032 2000年11月

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Photoluminescence property of self-assembled InAs/GaAs quantum dots on GaAs(211)A at low coverage（共著）

K. Ohnishi, P. O. Vaccaro, K. Hara, I. Umezu and A. Sugimura

Mem. konan Univ., Sci Ser. 47(1), 21 - 29 2000年11月

共著

Optical Properties of Self-assembled InAs Quantum Dots Grown on GaAs(211)A Substrates（共著）

A. Sugimura, K. Ohnishi, I. Umezu and P. O. Vaccaro

Thin film solids 380, 97 - 100 2000年11月

共著

Correlation between photoluminescence intensity and micro structure in amorphous silicon films prepared by reactive RF sputtering

Umezu I, Murota T, Kawata M, Takashima Y, Yoshida K, Inada M, Sugimura A

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 39 ( 8B ) L844 - L846 2000年8月

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DOI： 10.1143/jjap.39.L844

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A comparative study of the photoluminescence properties of a-SiOx : H film and silicon nanocrystallites

Umezu I, Yoshida K, Sugimura A, Inokuma T, Hasegawa S, Wakayama Y, Yamada Y, Yoshida T

JOURNAL OF NON-CRYSTALLINE SOLIDS 266 1029 - 1032 2000年5月

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DOI： 10.1016/S0022-3093(99)00896-0

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Optical properties of single-wall carbon nanotubes

Kataura H, Kumazawa Y, Maniwa Y, Umezu I, Suzuki S, Ohtsuka Y, Achiba Y

SYNTHETIC METALS 103 ( 1-3 ) 2555 - 2558 1999年6月

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DOI： 10.1016/S0379-6779(98)00278-1

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Effects of thermal processing on photoluminescence of Si nanocrystallites prepared by pulsed laser ablation

Umezu I, Shibata K, Yamaguchi S, Sato H, Sugimura A, Yamada Y, Yoshida T

PROCEEDINGS OF THE FIFTH INTERNATIONAL SYMPOSIUM ON QUANTUM CONFINEMENT: NANOSTRUCTURES 98 ( 19 ) 40 - 48 1999年

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Optical absorption and resonance Raman scattering of carbon nanotubes

Kataura H, Kumazawa Y, Kojima N, Maniwa Y, Umezu I, Masubuchi S, Kazama S, Zhao X, Ando Y, Ohtsuka Y, Suzuki S, Achiba Y

ELECTRONIC PROPERTIES OF NOVEL MATERIALS - SCIENCE AND TECHNOLOGY OF MOLECULAR NANOSTRUCTURES 486 328 - 332 1999年

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Effects of thermal processes on photoluminescence of silicon nanocrystallites prepared by pulsed laser ablation

Umezu I, Shibata K, Yamaguchi S, Sugimura A, Yamada Y, Yoshida T

JOURNAL OF APPLIED PHYSICS 84 ( 11 ) 6448 - 6450 1998年12月

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DOI： 10.1063/1.368971

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Nano-oxidation of vanadium thin films using atomic force microscopy

Vaccaro PO, Sakata S, Yamaoka S, Umezu I, Sugimura A

JOURNAL OF MATERIALS SCIENCE LETTERS 17 ( 22 ) 1941 - 1943 1998年11月

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DOI： 10.1023/A:1006616711693

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Effect of plasma treatment on the density of defects at an amorphous Si : H-insulator interface

Umezu I, Kuwamura T, Kitamura K, Tsuchida T, Maeda K

JOURNAL OF APPLIED PHYSICS 84 ( 3 ) 1371 - 1377 1998年8月

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DOI： 10.1063/1.368249

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Defect formation mechanism during plasma enhanced chemical vapor deposition of undoped a-Si : H

Maeda K, Umezu I

JOURNAL OF NON-CRYSTALLINE SOLIDS 227 43 - 47 1998年5月

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DOI： 10.1016/S0022-3093(98)00266-X

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A study of interface state density between a-Si : H and insulating layer in terms of plasma surface reaction

Umezu I, Tsuchida T, Maeda K

JOURNAL OF NON-CRYSTALLINE SOLIDS 227 1235 - 1239 1998年

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DOI： 10.1016/S0022-3093(98)00307-X

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Temperature-dependent photoluminescence of silicon nanocrystallites prepared by inert-gas-ambient pulsed laser ablation

Umezu I, Yamaguchi S, Shibata K, Sugimura A, Yamada Y, Yoshida T

MATERIALS AND DEVICES FOR SILICON-BASED OPTOELECTRONICS 486 219 - 224 1998年

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Defect formation during deposition of undoped a-Si:H by rf glow discharge

Maeda K, Umezu I, Ishizuka H

PHYSICAL REVIEW B 55 ( 7 ) 4323 - 4331 1997年2月

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DOI： 10.1103/PhysRevB.55.4323

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Defect formation mechanism during PECVD of a-Si : H

Maeda K, Umezu I

AMORPHOUS AND MICROCRYSTALLINE SILICON TECHNOLOGY - 1997 467 573 - 578 1997年

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DOI： 10.1557/PROC-467-573

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Investigation of interface state density between a-Si:H and insulating layers by ESR and photothermal deflection spectroscopy

Umezu I, Kitamura K, Maeda K

JOURNAL OF NON-CRYSTALLINE SOLIDS 198 778 - 781 1996年5月

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DOI： 10.1016/0022-3093(96)00011-7

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Optical properties of silicon nanocrystallites prepared by excimer laser ablation in inert gas

Yamada Y, Orii T, Umezu I, Takeyama S, Yoshida T

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 35 ( 2B ) 1361 - 1365 1996年2月

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DOI： 10.1143/JJAP.35.1361

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Defect formation during deposition of undoped a-Si:H by PECVD

Maeda K, Umezu I

AMORPHOUS SILICON TECHNOLOGY - 1996 420 569 - 574 1996年

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DOI： 10.1557/PROC-420-569

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Optical properties of silicon nanocrystallites prepared by pulsed laser ablation in inert gas ambient

Yoshida T, Yamada Y, Takeyama S, Orii T, Umezu I, Makita Y

LASER PROCESSING OF MATERIALS AND INDUSTRIAL APPLICATIONS 2888 6 - 13 1996年

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DOI： 10.1117/12.253105

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A COMPARATIVE-STUDY ON STRUCTURAL AND ELECTRONIC-PROPERTIES OF PECVD A-SIOX WITH A-SINX

MAEDA K, SAKAMOTO N, UMEZU I

JOURNAL OF NON-CRYSTALLINE SOLIDS 187 287 - 290 1995年7月

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DOI： 10.1016/0022-3093(95)00151-4

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MECHANISM OF SURFACE-REACTION IN THE DEPOSITION PROCESS OF ALPHA-SI-H BY RF GLOW-DISCHARGE

MAEDA K, KUROE A, UMEZU I

PHYSICAL REVIEW B 51 ( 16 ) 10635 - 10645 1995年4月

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DOI： 10.1103/PhysRevB.51.10635

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OPTICAL-BOND GAP AND TAUC GAP IN A-SIOX-H AND A-SINX-H FILMS

UMEZU I, MIYAMOTO K, SAKAMOTO N, MAEDA K

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 34 ( 4A ) 1753 - 1758 1995年4月

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DOI： 10.1143/JJAP.34.1753

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ANALYSIS OF JOULE HEAT IN A-SI-H FILM BY PHOTOTHERMAL DETECTION SPECTROSCOPY

UMEZU, I, K MAEDA

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 33 ( 10 ) 5647 - 5651 1994年10月

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出版者・発行元：JAPAN J APPLIED PHYSICS

Photothermal deflection (PD) signals without applied bias are a direct observation of nonradiative recombination processes of photoexcited carriers, which strongly correlate with photocurrent under applied bias. The PD signal under DC bias was carefully compared with the photocurrent (PC) signal in the energy region around and above the band gap. A large dip, which was not observed in PC spectra, was observed in PD spectra in the spectral region near the absorption edge. This spectral feature was discussed from the standpoint of Joule heat due to drift of photocarriers. We have pointed out that dark Joule heat (W-d) and effective applied voltage (V-s) are important in analysis. By taking into account these parameters, the experimental spectrum of PD signals under DC bias was successfully reproduced. It is concluded that variation of V-s which arises from large photosensitivity causes a dip in PD spectra. No evidence of the photon energy dependence of the recombination process was observed in PD spectra.

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DEPLETION LAYER WIDTH IN UNDOPED A-SI-H SCHOTTKY-BARRIER REVEALED BY REVERSE BIAS PHOTOCURRENT

K MAEDA, W CHIYODA, UMEZU, I, A KUROE

JOURNAL OF APPLIED PHYSICS 75 ( 7 ) 3522 - 3529 1994年4月

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出版者・発行元：AMER INST PHYSICS

Reverse bias photocurrent of undoped a-Si:H Schottky barrier was investigated under excitation with uniformly absorbed light. Dependence of the photocurrent on the applied voltage V gives unambiguous dependence of the depletion layer width W on voltage V, which cannot be obtained by conventional capacitance-voltage measurements for undoped a-Si:H. There are two voltage ranges giving parabolic dependence of W with different apparent ionized donor densities due to a spatial variation of the space-charge density. These observations are considered to be characteristic of semiconductors with major deep gap states of large energy width. The experimental results were analyzed using a simple model of energy distribution of the gap state density of dividing the depletion layer into two. In one of these deep depletion occurs. The variation of the apparent W-V relation observed upon lowering the exciting photon energy was analyzed to be related to a decrease in the absorption coefficient with the applied voltage due to an emptying of the initial states of the gap state absorption. Results of the analysis are consistent with the electron-spin density observed in the same undoped a-Si:H.

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Analysis of joule heat in a-Si:H film by photothermal deflection spectroscopy

Ikurou Umezu, Keiji Maeda

Japanese Journal of Applied Physics 33 ( 10R ) 564 - 561 1994年

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Photothermal deflection (PD) signals without applied bias are a direct observation of nonradiative recombination processes of photoexcited carriers, which strongly correlate with photocurrent under applied bias. The PD signal under DC bias was carefully compared with the photocurrent (PC) signal in the energy region around and above the band gap. A large dip, which was not observed in PC spectra, was observed in PD spectra in the spectral region near the absorption edge. This spectral feature was discussed from the standpoint of Joule heat due to drift of photocarriers. We have pointed out that dark Joule heat (W d) and effective applied voltage (V S) are important in analysis. By taking into account these parameters, the experimental spectrum of PD signals under DC bias was successfully reproduced. It is concluded that variation of V S which arises from large photosensitivity causes a dip in PD spectra. No evidence of the photon energy dependence of the recombination process was observed in PD spectra. © 1994 IOP Publishing Ltd.

DOI： 10.1143/JJAP.33.5647

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INTERFACE STATE DENSITY OF SINX-H/C-SI MIS STRUCTURE

MAEDA K, JINNAI T, UMEZU I

JOURNAL OF NON-CRYSTALLINE SOLIDS 166 849 - 852 1993年12月

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ATOMIC MICROSTRUCTURE AND ELECTRONIC-PROPERTIES OF A-SINX-H DEPOSITED BY PECVD

MAEDA K, UMEZU I

JOURNAL OF NON-CRYSTALLINE SOLIDS 137 883 - 886 1991年12月

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DOI： 10.1016/S0022-3093(05)80261-3

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INVESTIGATION OF SINX-H/SI INTERFACE BY CAPACITANCE METHOD

K MAEDA, UMEZU, I, A KAWAGUCHI

APPLIED PHYSICS LETTERS 59 ( 19 ) 2421 - 2423 1991年11月

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出版者・発行元：AMER INST PHYSICS

A new capacitance method was developed to investigate properties of the SiN(x):H/c-Si interface. By comparison of the frequency dependence of C-V characteristics of p- and n-type c-Si substrate sample pairs, flatband voltage for an intrinsic substrate sample can be determined. Analyses of two kinds of frequency dependence, i.e., the variation of voltage at flatband capacitance and the variation of capacitance at flatband voltage, disclose different aspects of the interface state density with respect to the energy level in the band gap, response time, and ionized state. Donor states are predominant in the investigated interface.

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STRUCTURE OF AMORPHOUS SINX-H STUDIED BY PHOTOEMISSION AND INFRARED-ABSORPTION

UMEZU, I, K MAEDA

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 30 ( 10 ) 2547 - 2552 1991年10月

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出版者・発行元：JAPAN J APPLIED PHYSICS

We present an X-ray photoemission (XPS) and infrared absorption (IR) study of hydrogenated amorphous silicon-nitride (SiNx:H) films which were prepared by plasma decomposition of SiH4 and NH3. Both Si 2p (XPS) and Si-H (IR) peaks are decomposed to contributions from Si-centered tetrahedrons. The peak shift in both XPS and IR can be divided into two compositional regions: below and above x = 1.0. Peak energy increases gradually with x until it reaches 1.0. For x > 1.0, the increment of peak shift is small. There are no particular features at around stoichiometric composition, x = 1.33. The kink point at around x = 1.0 and maximum composition of x = 1.7 are discussed in terms of Si-centered tetrahedrons. The Si-Si bond, which decreased with increasing source gas ratio R (R = [NH3]/[SiH4]), did not disappear even though a large gas ratio R was given. This feature is important in accounting for the structure of the films.

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ATOMIC MICROSTRUCTURE AND ELECTRONIC-PROPERTIES OF A-SINX-H DEPOSITED BY RADIO-FREQUENCY GLOW-DISCHARGE

K MAEDA, UMEZU, I

JOURNAL OF APPLIED PHYSICS 70 ( 5 ) 2745 - 2754 1991年9月

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出版者・発行元：AMER INST PHYSICS

a-SiN(x):H films of various composition x were deposited by rf glow discharge (GD). The deposition rate was analyzed for three ranges of gas flow ratio R = [NH3]/[SiH-4] depending on the deposition mechanism. Properties of these films were measured by means of x-ray photoelectron spectroscopy (XPS), infrared (IR) absorption, optical absorption, and the temperature dependence of electrical conductivity. The composition x was determined by XPS. For large values of R, x was found to be saturated at 1.7. The variation of H content was detected by IR absorption. The variation of coordinating atoms of Si with increasing x was deduced from the variation of XPS spectra of the Si 2p core-level and the shift of Si-H stretching vibration frequency in IR absorption. Based on the random bonding model and assuming bonding units to the central Si atom to be Si, N, and NH, probabilities of Si tetrahedra with various coordinating units were obtained. The results indicate that there are many Si-Si bonds for the stoichiometric x = 1.33 and that the concentration of Si-Si bonds diminishes at around the saturation value x = 1.7. These results seem to imply that the presence of Si-Si bonds to some extent is a prerequisite condition for film deposition by GD. Experimental results of optical absorption analyzed by Tauc relation revealed the presence of two kinds of x region whose properties are quite different. For x < 1.5, its optical absorption is similar to a-Si:H modified by the presence of N. With increasing x, the optical band gap E(O) increases and B coefficient in the Tauc plot decreases. At about x = 1.5, Si-Si bonding effectively disappears and the optical absorption abruptly changes to that similar to beta-Si3N4. Considering these results, the change of electronic band structure with x was deduced on the basis of the atomic structure obtained above and by the tight binding approximation. For x < 1.5, the optical band gap is due to Si-Si bonding, the energy gap of which increases, and the linear band tail becomes broad with increasing x. From the observed temperature dependence of conductivity, variations of the activation energy and pre-exponential factor are obtained with x up to x = 1.0. For the decrease of conductivity with x, the contribution from the pre-exponential factor is much larger than that from the activation energy. This result can be understood by a transport mechanism in the electronic band structure obtained above. Finally, it is concluded that the electronic properties of a-SiN(x):H deposited by GD ranging from semiconductor to insulator can be explained by the atomic microstructure and the electronic energy band structure.

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NONIDEAL J-V CHARACTERISTICS AND INTERFACE STATES OF AN A-SI-H SCHOTTKY-BARRIER

K MAEDA, UMEZU, I, T YOSHIMURA, H IKOMA

JOURNAL OF APPLIED PHYSICS 68 ( 6 ) 2858 - 2867 1990年9月

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出版者・発行元：AMER INST PHYSICS

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光音響法による非輻射遷移過程の研究

梅津郁朗

1990年3月

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A comparative study of photoluminescence properties of a-SiOx:H film and silicon nanocrystallites（共著）

I. Umezu, K. Yoshida, A. Sugimura, T. Inokuma, S. Hasegawa, Y. Wakayama, Y.　Yamada and T. Yoshida

- 1111年11月

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担当区分：筆頭著者

A comparative study of photoluminescence properties of a-SiOx:H film and silicon nanocrystallites

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