Details of a Researcher - HAMANAKA Yasushi

Photoexcited Carrier Transfer in CuInS₂ Nanocrystal Assembly by Suppressing Resonant-Energy Transfer Reviewed

Yasushi Hamanaka, Satoshi Okuyama, Rin Yokoi, Toshihiro Kuzuya, Keiki Takeda, Chihiro Sekine

ChemPhysChem 24 ( 21 ) e202300029-1 - e202300029-8 2023.08

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： https://doi.org/10.1002/cphc.202300029

Fabrication of two-dimensional hybrid organic-inorganic lead halide perovskites with controlled multilayer structures by liquid phase laser ablation Reviewed

Yoshimasa Fukuta, Takumi Miyata, Yasushi Hamanaka

Journal of Materials Chemistry C 11 ( 3 ) 910 - 916 2023.01

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1039/d2tc04395e

Size-dependent radiative recombination characteristics of isolated CuInS₂ nanocrystals Reviewed

Journal of Luminescence 252 119353-1 - 119353-7 2022.09

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1016/j.jlumin.2022.119353

Luminescence Enhancement in CuInS₂ Nanoparticles through the Selective Passivation of Nonradiative Recombination Sites by Phosphine Ligands Reviewed

Koichiro Suzuki, Toshihiro Kuzuya, and Yasushi Hamanaka

Journal of Physical Chemistry C 126 ( 39 ) 16751 - 16758 2022.09

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1021/acs.jpcc.2c05187

Synthesis and Analysis of Highly Monodispersed Silver Copper Sulfide Nanoparticles Reviewed

Kenshiro Sato, Toshihiro Kuzuya, Yasushi Hamanaka, Shinji Hirai

MATERIALS TRANSACTIONS 62 ( 6 ) 731 - 737 2021.05

Language：English Publishing type：Research paper (scientific journal) Publisher：The Japan Institute of Metals and Materials (JIM)

DOI： 10.2320/matertrans.MT-M2020395

Non-vacuum fabrication of bandgap-controlled CZTGS alloy films using CZTS+CZGS mixed nanoparticle inks Reviewed International journal

Y. Hamanaka, K. Matsumoto

Materials Science Forum 1016 509 - 515 2021.01

Authorship：Lead author Language：English Publishing type：Research paper (international conference proceedings) Publisher：Trans Tech Publications Ltd

Ligand-induced luminescence transformation in AgInS₂ nanoparticles:From defect emission to band-edge emission Reviewed International journal

Akemitsu Hirase, Yasushi Hamanaka, Toshihiro Kuzuya

Journal of Physical Chemistry Letters 11 3969 - 3974 2020.04

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：ACS publications

DOI： 10.1021/acs.jpclett.0c01197

Luminescence enhancement mechanisms of AgInS₂/ZnS core/shell nanoparticles fabricated by suppressing quaternary alloying Reviewed International journal

Yasushi Hamanaka, Kento Watanabe, Toshihiro Kuzuya

Journal of Luminescence 217 116794 2019.09

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier

DOI： https://doi.org/10.1016/j.jlumin.2019.116794

Luminescence enhancement mechanisms of AgInS2/ZnS core/shell nanoparticles fabricated by suppressing quaternary alloying Reviewed

Yasushi Hamanaka, Kento Watanabe, Toshihiro Kuzuya

Journal of Luminescence 217 116794 2019.09

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier

DOI： 10.1016/j.jlumin.2019.116794

Syntheis of Ag／AgCuS／CuInS₂ hybrid nanoparticles by reductive cation exchange and their asymmetric heterostructure Reviewed International journal

T. Kuzuya, T. Kuwada, H. Inukai, Y. Hamanaka, S. Hirai

Applied Surface Science 493 1278 - 1285 2019.07

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier

DOI： 10.1016/j.apsusc.2019.07.129

Anisotropic licalized surface plasmon resonances in CuS nanoplates prepared by size-selective precipitation Reviewed International journal

Yasushi Hamanaka, Kaoru Yamada, Tatusnori Hirose, Toshihiro Kuzuya

Japanese Journal of Applied Physics 57 055201 2018.04

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.7567/JJAP.57.055201

Plasmonic Optical Nonlinearities of Copper Sulfide Nanoparticles Reviewed International journal

Hamanaka, Y., Hirose, T., Yamada, K., Miyagawa, K., & Kuzuya, T.

MRS Advances 3 ( 14 ) 741 - 746 2018.01

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1557/adv.2018.91

Fabrication of oxidation-resistant Ge colloidal nanoparticles by pulsed laser ablation in aqueous HCl Reviewed International journal

Yasushi Hamanaka, Masahiro Iwata, Junichi Katsuno

Applied Physics A 123 425 2017.05

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：Springer

DOI： 10.1007/s00339-017-1044-9

Synthesis of Ag/CuInS2 Core-Shell Nanoparticles Reviewed

Toshihiro Kuzuya, Takahiko Kuwada, Yasushi Hamanaka, Shinji Hirai

MATERIALS TRANSACTIONS 58 ( 1 ) 65 - 70 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：JAPAN INST METALS

In this work, the facile synthesis of Ag/CuInS2 composite nanoparticles (NPs) with a core-shell structure is demonstrated for the first time. In our procedure, the pre-formed Ag NPs were subsequently coated with a CuInS2 shell through the thermal decomposition of the metal thiolate complex. The Ag/CuInS2 composite NPs took Ag core-CuInS2 shell structures (Ag(CuInS2) when an oleic acid-oloylamine mixture was used as the co-surfactant. High-resolution transmission electron microscopy (TEM) indicated the epitaxial growth of the CuInS2 shell on the Ag NPs. In the extinction spectrum of the Ag@CuInS2 NPs, the localized surface plasmon resonance (LSPR) peak of the Ag core broadened and red-shifted to 2.21 eV, confirming that the CuInS2 can he tuned by the CuInS2 shell. Finite-difference time-domain (FDTD) simulations indicated the enhancement of the electric field in the CuInS2 shell region and the surface of the A(2)@CulnS(2) NPs. This enhancement effect may improve the efficiency of incident light absorption in CuInS2 quantum dot sensitized solar cells.

DOI： 10.2320/matertrans.M2016026

Synthesis of highly non-stoichiometric Cu₂ZnSnS₄ nanoparticles with tunable bandgaps Reviewed International journal

Yasushi Hamanaka, Wataru Oyaizu, Masanari Kawase, Toshihiro Kuzuya

Journal of Nanoparticle Research 19 ( 1 ) 9 2016.12

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：Springer

DOI： 10.1007/s1105-016-3704-7

Synthesis of highly non-stoichiometric Cu2ZnSnS4 nanoparticles with tunable bandgaps Reviewed

Yasushi Hamanaka, Wataru Oyaizu, Masanari Kawase, Toshihiro Kuzuya

JOURNAL OF NANOPARTICLE RESEARCH 19 ( 1 ) 9 2016.12

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

Non-stoichiometric Cu2ZnSnS4 nanoparticles with average diameters of 4-15 nm and quasipolyhedral shape were successfully synthesized by a colloidal method. We found that a non-stoichiometric composition of Zn to Cu in Cu2ZnSnS4 nanoparticles yielded a correlation where Zn content increased with a decrease in Cu content, suggesting formation of lattice defects relating to Cu and Zn, such as a Cu vacancy (V-Cu), antisite with Zn replacing Cu (Zn-Cu), and/or defect cluster of V-Cu and Zn-Cu. The bandgap energy of Cu2ZnSnS4 nanoparticles systematically varies between 1.56 and 1.83 eV depending on the composition ratios of Cu and Zn, resulting in a wider bandgap for Cu-deficient Cu2ZnSnS4 nanoparticles. These characteristics can be ascribed to the modification in electronic band structures due to formation of V-Cu and Zn-Cu on the analogy of ternary copper chalcogenide, chalcopyrite CuInSe2, in which the top of the valence band shifts downward with decreasing Cu contents, because much like the structure of CuInSe2, the top of the valence band is composed of a Cu 3d orbital in Cu2ZnSnS4.

DOI： 10.1007/s11051-016-3704-7

Synthesis of Ag/CuInS₂ Core-Shell Nanoparticles Reviewed

Toshihiro Kuzuya, Takahiko Kuwada, Yasushi Hamanaka, Shinji Hirai

Materials Transactions 58 ( 1 ) 65 - 70 2016.11

Language：English Publishing type：Research paper (scientific journal)

Synthesis of Ag/CuInS2 Core-Shell Nanoparticles Reviewed

Toshihiro Kuzuya, Takahiko Kuwada, Yasushi Hamanaka, Shinji Hirai

Materials Transactions 58 ( 1 ) 65 - 70 2016.11

Language：English Publishing type：Research paper (scientific journal)

Plasmonic enhancement of third-order nonlinear optical susceptibilities in self-doped Cu_2-xS nanoparticles Reviewed International journal

YASUSHI HAMANAKA,TATSUNORI HIROSE,KAORU YAMADA, TOSHIHIRO KUZUYA

Optical Materials Express 6 ( 12 ) 3838 - 3848 2016.11

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal) Publisher：Optical Society of America

DOI： 10.1364/OME.6.003838

硫化銅ナノ粒子の近赤外局在表面プラズモン共鳴の三次光学非線形性 Invited

濱中　泰

分子科学研究所　機器センターたより８ 87 - 90 2016.07

Authorship：Lead author Language：Japanese Publishing type：Research paper (bulletin of university, research institution) Publisher：分子科学研究所機器センター

Localized surface plasmon resonance in Cu2-xS nanoparticles V

Yamada Kaoru, Hirose Tatsunori, Hamanaka Yasushi, Kuzuya Toshihiro

Meeting Abstracts of the Physical Society of Japan 71 1363 - 1363 2016

Language：Japanese Publisher：The Physical Society of Japan

DOI： 10.11316/jpsgaiyo.71.2.0_1363

CiNii Articles

Structural transformation and photoluminescence modification of AgInS₂ nanoparticles induced by ZnS shell formation Reviewed

Yasushi Hamanaka, Daichi Yukitoki, Toshihiro Kuzuya

Applied Physics Express 8 095001-1 - 095001-4 2015.09

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.7567/APEX.8.095001

Enhancement of Donor-Acceptor Pair Emissions in Colloidal AgInS₂ Quantum Dots with High Concentrations of Defects Reviewed

Yasushi Hamanaka, Kohei Ozawa, Toshihiro Kuzuya

Journal of Physical Chemistry (C) 118 ( 26 ) 14562 - 14568 2014.06

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1021/jp501429f

Solution-phase synthesis and photoluminescence characterization of quaternary Cu₂ZnSnS₄ nanocrystals Reviewed

Y. Hamanaka. M. Tsuzuki, K. Ozawa, T. Kuzuya

AIP Conerence Proceedings 1566 3 - 4 2013.12

Authorship：Lead author Language：English Publishing type：Research paper (international conference proceedings)

Resonant enhancement of third-order nonlinear optical susceptibilities of Cd-free chalcopyrite nanocrystals within quantum confinement regime Reviewed

Yasushi Hamanaka, Tetsuya Ogawa, Masakazu Tsuzuki, Toshihiro Kuzuya, Kenji Sumiyama

Applied Physics Letters 103 ( 5 ) 053116-1 - 053116-4 2013.08

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

Luminescence properties of chalcopyrite AgInS₂ nanocrystals: Their origin and related electronic states Reviewed

Yasushi Hamanaka, Tetsuya Ogawa, Masakazu Tsuzuki, Kohei Ozawa, Toshihiro Kuzuya

Journal of Luminescence 133 121 - 124 2013.01

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1016/j.jlumin.2011.10.006

Other Link： http://www.sciencedirect.com/science/article/pii/S0022231311005722

Solution-phase Synthesis and Photoluminescence Characterization of Quaternary Cu2ZnSnS4 Nanocrystals Reviewed

Yasushi Hamanaka, Masakazu Tsuzuki, Kohei Ozawa, Toshihiro Kuzuya

PHYSICS OF SEMICONDUCTORS 1566 3 - + 2013

Language：English Publishing type：Research paper (international conference proceedings) Publisher：AMER INST PHYSICS

Cu2ZnSnS4 (CZTS) nanocrystals were synthesized via solution phase route and their lattice defects were investigated by photoluminescence measurements. Ionization energies of the defect levels were estimated to be 10 and 72 meV from thermal quenching behavior of the photoluminescence spectra. These values are quite different from those experimentally estimated for vapor-grown CZTS films and crystals and theoretically calculated for bulk CZTS. The results indicate that the defects are characteristic of CZTS nanocrystals synthesized in the solution phase.

DOI： 10.1063/1.4848256

Synthesis of Ag-In binary sulfide nanoparticles-structural tuning and their photoluminescence properties Reviewed

Phase Control and Its Mechanism of CuInS₂ Nanoparticles Reviewed

T. Kuzuya, Y. Hamanaka, K. Itoh, T. Kino, K. Sumiyama, Y. Fukunaka, S. Hirai

Journal of Colloid and Interface Science 2012.08

Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1016/j.jcis.2012.08.013

Crossover Phenomenon in Third-Order Nonlinear Optical Susceptibilities of Gold Nanoparticles from Plasmons to Discrete Electronic Stataes Reviewed

Y. Hamanaka, N. Okada, K. Fukagawa, A. Nakamura, Y. Tai, J. Murakami

Journal of Physical Chemistry (C) 116 10760 - 10765 2012.04

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1021/jp2121388

Photoluminescence properties and its origin of AgInS₂ quantum dots with chalcopyrite structure Reviewed

Yasushi Hamanaka, Tetsuya Ogawa, Masakazu Tsuzuki, Toshihiro Kuzuya

Journal of Physical Chemstry C 115 1786 - 1792 2011.01

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1021/jp110409q

Other Link： http://pubs.acs.org/doi/pdf/10.1021/jp110409q

T. Ogawa, T. Kuzuya, Y. Hamanaka and K. Sumiyama

Journal of Materials Chemistry 20 2226 - 2231 2010.02

Language：English Publishing type：Research paper (scientific journal)

DOI： 10.1039/b920732e

Other Link： http://www.rsc.org/ej/JM/2010/b920732e.pdf

Defect-induced photoluminescence and third-order nonlinear optical response of chemically synthesized chalcopyrite CuInS2 nanoparticles Reviewed

Y. Hamanaka, T. Kuzuya, T. Sofue, T. Kino, K. Itoh and K. Sumiyama

Chemical Physics Letters 466 176 - 180 2008.04

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

One-dimensional characteristics of third-order nonlinear optical response in single-walled carbon nanotubes Reviewed International journal

A. Nakamura, Y. Takahashi, S. Imamura, H. Kishida, Y. Hamanaka

AIP Conference Proceedings 893 1011 - 1011 2007

Language：English Publishing type：Research paper (international conference proceedings)

Non-linear optical response and relaxation dynamics in double-walled carbon nanotubes Reviewed

A. Nakamura, T. Tomikawa, M. Watanabe, Y. Hamanaka, Saito and H. Ago

Journal of Luminescence 119&120 8 - 12 2006.04

Language：English Publishing type：Research paper (scientific journal)

Ultrafast relaxation dynamics of electrons in Au clusters capped with dodecanethiol molecules Reviewed

Y. Hamanaka, K. Fukagawa, Y. Tai, J. Murakami and A. Nakamura

Journal of Luminescence 119&120 423 - 427 2006.04

Language：English Publishing type：Research paper (scientific journal)

Formation of J-aggregates of mixed merocyanine dyes in Langmuir-Blodgett films Reviewed

A. Nakamura, Y. Mizutani, N. Okuyama, Y. Hamanaka and S. Kuroda

Colloids and Surfaces A: Physicochem. Eng. Aspects 284&285 89 - 92 2006.04

Language：English Publishing type：Research paper (scientific journal)

Hierarchical structure of merocyanine J-aggregates prepared by Langmuir-Blodgett and spin-coating methods Reviewed

Y. Hamanaka, H. Kurasawa, A. Nakamura, Y. Uchiyama, K. Marumoto, and S. Kuroda

Colloids and Surfaces A: Physicochemical and Engineering Aspects 257&258 105 - 109 2005.04

Language：English Publishing type：Research paper (scientific journal)

Optical nonlinearities of metal nanoparticles with various shapes and sizes Reviewed

A. Nakamura, Y. Hamanaka, N. Okada, K. Fukuda, Y. Tai, J. Murakami, L. M. Liz-Marzan, P. Mulvany

Technical Report of IEICE OME2004-11 1 - 6 2005.04

Language：Japanese Publishing type：Research paper (scientific journal)

Linear and nonlinear optical response of silver nanoprisms: local electric fields of dipole and quadrupole plasmon resonances Reviewed

N. Okada, Y. Hamanaka, A. Nakamura, I. Pastoriza-Santos, and L. M. Liz-Marzán

Journal of Physical Chemistry B 108 8751 - 8755 2004.04

Language：English Publishing type：Research paper (scientific journal)

Enhancement of third-order nonlinear optical susceptibilities in silica-capped Au nanoparticle films with very high concentrations Reviewed

Y. Hamanaka, K. Fukuta, A. Nakamura, L. M. Liz-Marzán, and P. Mulvaney

Applied Physics Letters 84 4938 - 4940 2004.04

Language：English Publishing type：Research paper (scientific journal)

Ultrafast relaxation dynamics of photoexcited carriers in metallic and semioconducting single-walled carbon nanotubes Reviewed

M. Ichida, Y. Hamanaka, H. Kataura, Y. Achiba, and A. Nakamura

Journal of the Physical Society of Japan 73 3479 - 3483 2004.04

Language：English Publishing type：Research paper (scientific journal)

Ultrafast nonlinear optical response in silica-capped gold nanoparticle films Reviewed

Y. Hamanaka, K. Fukuta, A. Nakamura, L. M. Liz-Marzán, and P. Mulvaney

Journal of Luminescence 108 365 - 369 2004.04

Language：English Publishing type：Research paper (scientific journal)

Critical behavior of a photo-disordered spin system in epitaxial CrO2 films Reviewed

T. Yoshii, Y. Hamanaka, Y. Moritomo, and A. Nakamura

Journal of Luminescence 108 225 - 228 2004.04

Language：English Publishing type：Research paper (scientific journal)

Dispersion of third-order optical susceptibility around surface plasmon resonance in silver nanocrystal-glass composites Reviewed

Y. Hamanaka, N. Hayashi, A. Nakamura, and S. Omi

Journal of the Optical Society of America B 20 1227 - 1232 2003.04

Language：English Publishing type：Research paper (scientific journal)

Morphology of self-assembled merocyanine J-aggregates in films studied by scanning near-field optical microscope Reviewed

Y. Hamanaka, O. Kawasaki, T. Yamauchi, and A. Nakamura

Chemical Physics Letters 378 47 - 54 2003.04

Language：English Publishing type：Research paper (scientific journal)

Dispersion curves of complex third-order optical susceptibilities around the surface plasmon resonance in Ag nanocrystal-glass composites Reviewed

Yasushi Hamanaka, Arao Nakamura, Nobuhiro Hayashi, Shigeaki Omi

Journal of the Optical Society of America B: Optical Physics 20 ( 6 ) 1227 - 1232 2003

Language：English Publishing type：Research paper (scientific journal) Publisher：Optical Society of America (OSA)

We have investigated dispersion curves of a third-order nonlinear optical susceptibility, χ(3), around the surface-plasmon resonance energy for a Ag nanocrystal-glass composite by means of z-scan and degenerate four-wave mixing measurements. Real and imaginary parts of χ(3) of the composite that contains Ag nanocrystals with an average diameter of 7 nm have been measured at room temperature. The imaginary part of χ(3) exhibits a negative peak near the surface-plasmon resonance, and the largest negative value is -(1.5 ± 0.2) × 10-10 electrostatic units (esu). The real part of χ(3) changes from -(4 ± 2) × 10-11 esu at the lower energy side of the surface-plasmon peak to +(4.4 ± 0.5) × 10-11 esu at the higher energy side. We calculated dispersion curves for the composite assuming that the real and the imaginary parts of the dielectric constant of metal nanocrystals change by optical excitations that are due to the creation of hot electrons. The obtained dispersion curves show a characteristic feature that differs from the exciton system in semiconductors. © 2003 Optical Society of America.

DOI： 10.1364/JOSAB.20.001227

Ultrafast electron relaxation via breathing vibration of gold nanocrystals embedded in a dielectric medium Reviewed

Exciton delocalization length of merocyanine J-aggregates in Langmuir-Blodgett films studied from linear and nonlinear absorption measurements Reviewed

Y. Hamanaka, H. Kurasawa, A. Nakamura, Y. Uchiyama, K. Marumoto, and S. Kuroda

Chemical Physics Letters 363 233 - 240 2002.04

Language：English Publishing type：Research paper (scientific journal)

Femtosecond laser spectroscopy of In0.53Ga0.47As/InP multiple quantum wells: interfacial roughness and photoexcited carrier relaxation Reviewed

A. Nakamura, K. Tanase, I. Yamakawa, T. Yamauchi, Y. Hamanaka, R. Oga, Y. Fujiwara, and Y. Takeda

Journal of Luminescence 100 259 - 267 2002.04

Language：English Publishing type：Research paper (scientific journal)

Ultrafast relaxation dynamics of photoexcited states in semiconducting single-walled carbon nanotubes Reviewed

M. Ichida, Y. Hamanaka, H. Kataura, Y. Achiba, and A. Nakamur

Physica B 323 237 - 238 2002.04

Language：English Publishing type：Research paper (scientific journal)

Sol-gel derived gold nanoclusters in silica glass possessing large optical nonlinearities S. Tamil Selvan, T. Hayakawa, M. Nogami, Y. Kobayashi, L. M. Liz-Marzán, Y. Hamanaka, and A. Nakamura Reviewed

S. Tamil Selvan, T. Hayakawa, M. Nogami, Y. Kobayashi, L. M. Liz-Marzán, Y. Hamanaka, and A. Nakamura

Journal of Physical Chemistry B 106 10157 - 10162 2002.04

Language：English Publishing type：Research paper (scientific journal)

Structure and photoexcited carrier dynamics in InGaAs/InP multiple quantum wells Reviewed

I. Yamakawa, M. Shiozawa, Y. Wakui, K. Tanase, Y. Hamanaka, A. Nakamura, R. Oga, Y.

Technical Report of IEICE 35 - 40 2002

Language：English Publishing type：Research paper (scientific journal)

Ultrafast relaxation dynamics of photoexcited carriers in single-walled carbon nanotubes Reviewed International journal

M. Ichida, Y. Hamanaka, H. Kataura, Y. Achiba, and A. Nakamura

Proceedings of the 26th International Conference on the Physics of Semiconductors, Edinburgh, 2002

Language：English Publishing type：Research paper (international conference proceedings)

Femtosecond transient absorption study of merocyanine J-aggregates Reviewed

Y. Hamanaka, H. Kurasawa, A. Nakamura, Y. Uchiyama, K. Marumoto, and S. Kuroda

Journal of Luminescence 94&95 451 - 455 2001.04

Language：English Publishing type：Research paper (scientific journal)

Y. Hamanaka, J. Kuwabata, I. Tanahashi, S. Omi, and A. Nakamura

Physical Review B 63 104302 2001.04

Language：English Publishing type：Research paper (scientific journal)

Primary processes of charge carrier generation in photoconducting polymers Reviewed

E. Farankevich, H. Ishii, Y. Hamanaka, T. Yokoyama, A. Fujii, S. Li, K. Yoshino, A. Nakamura, and K. Seki

Synthetic Metals 119 495 - 498 2001.04

Language：English Publishing type：Research paper (scientific journal)

Electron energy relaxation dependent on size and matrix in gold-nanocrystal-dielectric composites Reviewed International journal

Y. Hamanaka, J. Kuwabata, A. Nakamura, I. Tanahashi, and S. Omi

Springer Series in Chemical Physics 66 401 - 403 2001

Authorship：Lead author Language：English Publishing type：Research paper (international conference proceedings)

Ultrafast relaxation dynamics of photoexcited carriers in an InGaAs/InP multiple quantum well Reviewed International journal

Y. Hamanaka, A. Nakamura, K. Tanase, R. Ohga, Y. Nonogaki, Y. Fujiwara, and Y. Takeda

Springer Proceedings in Physics 87 621 - 622 2001

Authorship：Lead author Language：English Publishing type：Research paper (international conference proceedings)

Ultrafast electron relaxation via breathing vibration of gold nanocrystals embedded in a dielectric medium Reviewed

Y. Hamanaka, J. Kuwabata, I. Tanahashi, S. Omi, A. Nakamura

Physical Review B - Condensed Matter and Materials Physics 63 ( 10 ) 1043021 - 1043025 2001

Language：English Publishing type：Research paper (scientific journal)

Relaxation dynamics of electrons in gold nanocrystals with diameters of 3.0-17.5 nm embedded in SiO2, Al2O3, and TiO2 matrices have been investigated by means of femtosecond pump and probe spectroscopy. The experiments show that the energy relaxation rates depend on both the nanocrystal size and the matrix material. A model taking account of electron-breathing mode interaction, electron-bulk phonon interaction, and thermal diffusion through the interface can explain well the observed results. The breathing mode damping in the medium on a time scale of a few picoseconds plays an important role in the electron-energy dissipation process of the nanoscale composite system.

DOI： 10.1103/PhysRevB.63.104302

Ultrafast relaxation dynamics of photoexcited carriers in an In0.53Ga0.47As/InP multiple-quantum well Reviewed

Y Hamanaka, A Nakamura, K Tanase, R Ohga, Y Nonogaki, Y Fujiwara, Y Takeda

PROCEEDINGS OF THE 25TH INTERNATIONAL CONFERENCE ON THE PHYSICS OF SEMICONDUCTORS, PTS I AND II 87 621 - 622 2001

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPRINGER-VERLAG BERLIN

We heve investigated relaxation dynamics of photoexcited carriers and formation dynamics of excitons in a 10 nm-In0.53Ga0.47As/InP multiple quantum well at 77 X by femtosecond pump and probe spectroscopy. The observed spectral change of the exciton absorption band induced by the pump pulse is composed of broadening and bleaching components. The spectral broadening is attributed to scattering between excitons created by the probe pulse and free carriers generated by the pump pulse, and the bleaching is mainly due to the phase space filling. The time evolution of the absorption change shows that formation of excitons occurs on a time scale of similar to 20 ps after the intraband relaxation of photoexcited carriers.

Formation of polaron pairs and time-resolved photogeneration of free carriers in pi-conjugated polymers Reviewed

Electron dynamics and surface plasmon resonance nonlinearities in metal nanoparticles Reviewed

N. Del Fatti, F. Vallee, C. Flytzanis, Y. Hamanaka, and A. Nakamura

Chemical Physics 251 215 - 226 2000.04

Language：English Publishing type：Research paper (scientific journal)

E. Frankevich, H. Ishii, Y. Hamanaka, T. Yokoyama, A. Fuji, S. Li, K. Yoshino, A. Nakamura, and K. Seki

Physical Review B 62 2505 - 2515 2000.04

Language：English Publishing type：Research paper (scientific journal)

Dispersion of third-order nonlinear optical susceptibility of silver nanocrystal-glass composites Reviewed

Y. Hamanaka, N. Hayashi, A. Nakamura, and S. Omi

Journal of Luminescence 87-89 859 - 861 2000.04

Language：English Publishing type：Research paper (scientific journal)

Dispersion of third-order nonlinear optical susceptibility of silver nanocrystal-glass composites Reviewed

Y. Hamanaka, N. Hayashi, A. Nakamura, S. Omi

Journal of Luminescence 87 859 - 861 2000

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier Science Publishers B.V.

We have investigated dispersion of third-order nonlinear optical susceptibility, χ(3), for a silver nanocrystal-glass composite around the surface plasmon resonance band. A real and an imaginary part of χ(3) have been separately measured by a Z-scan method. The maximum value of imaginary χ(3) is -1.5 × 10-10 esu at 2.97 eV and the real χ(3) value ranges from -4.4 × 10-11 to +4.4 × 10-11 esu. We have calculated dispersion curves of the composite assuming that the real and imaginary parts of dielectric constant of metal nanocrystals are changed due to the creation of hot electrons by optical excitation. The dispersion curves near the surface plasmon band show features characteristic of the composite system, which is not described by a two-level atomic model.

DOI： 10.1016/S0022-2313(99)00442-1

Formation of polaron pairs and time-resolved photogeneration of free charge carriers in-conjugated polymers Reviewed

Eugene Frankevich, Hisao Ishii, Yasushi Hamanaka, Takahiro Yokoyama, Akihiko Fuji, Sergey Li, Katsumi Yoshino, Arao Nakamura, Kazuhiko Seki

Physical Review B - Condensed Matter and Materials Physics 62 ( 4 ) 2505 - 2515 2000

Language：English Publishing type：Research paper (scientific journal)

We have performed in the present work time-resolved experiments on poly(3-dodecyl-thiophene) (P3DDT) and poly(2,5-dioctyloxy-(Formula presented)-phenylene vinylene) (OO-PPV) films by directly probing the formation of charge carriers responsible for the cw photoconductivity within the time domain of -10 ps to 1 ns. Laser light pulses of 400 nm wavelength, 150 fs width, induced photoconductivity in a sample with a frequency 1 kHz. Red 800 nm light pulses delayed in respect to blue ones were revealed to affect the photoconductivity. The effect of the second pulses increased with the delay time. Red light induced changes of the photoconductivity were positive in OO-PPV, and negative in P3DDT. These results are rationalized as an evidence of delayed not immediate formation of free charge carriers. The carriers seem to be formed within 10 ps after the pumping pulse. A mechanism of formation of free polarons from polaron pair is suggested, which has permitted to explain main feature of the results including different signs of the effect of the red light in different polymers. © 2000 The American Physical Society.

DOI： 10.1103/PhysRevB.62.2505

Linear and nonlinear optical response in metal nanocrystal-doped glasses Reviewed

A. Nakamura, Y. Hamanaka, and S. Omi

Bulletin of Cluster Science and Technology 2 17 - 23 1999.04

Language：Japanese Publishing type：Research paper (scientific journal)

A facile sol-gel method for the encapsulation of gold nanoclusters in silica gels and their optical properties Reviewed

S. Tamil Selvan, M. Nogami, A. Nakamura, and Y. Hamanaka

Journal of Noncrystalline Solids 255 254 - 258 1999.04

Language：English Publishing type：Research paper (scientific journal)

Ultrafast response of nonlinear refractive index of silver nanocrystals embedded in glass Reviewed

Multiphoton Reduction of Eu3+ to Eu2+ in methanol using intense, short pulses from a Ti:sapphire laser Reviewed

N. Nakashima, S. Nakamura, S. Sakabe, H. Schillinger, Y. Hamanaka, C. Yamanaka, M. Kusaba, N. Ishihara, and Y. Izawa

Journal of Physical Chemistry A 103 3910 - 3916 1999.04

Language：English Publishing type：Research paper (scientific journal)

Hot carrier relaxation dynamics in In0.53Ga0.47As studied by femtosecond pump-probe spectroscopy Reviewed

D. Nishiwaki, Y. Hamanaka, Y. Nonogaki, Y. Fujiwara, Y. Takeda, and A. Nakamura

Journal of Luminescence 83&84 49 - 53 1999.04

Language：English Publishing type：Research paper (scientific journal)

Femtosecond relaxation dynamics of hot carriers in photoexcited In0.53Ga0.47As Reviewed

Y. Hamanaka, D. Nishiwaki, Y. Nonogaki, Y. Fujiwara, Y. Takeda, and A. Nakamura

Physica B 272 391 - 393 1999.04

Language：English Publishing type：Research paper (scientific journal)

Y. Hamanaka, A. Nakamura, S. Omi, N. Del Fatti, F. Vallee, and C. Flytzanis

Applied Physics Letters 75 1712 - 1714 1999.04

Language：English Publishing type：Research paper (scientific journal)

Hot carrier relaxation dynamics in In<inf>0.53</inf>Ga<inf>0.47</inf>As studied by femtosecond pump-probe spectroscopy Reviewed

D. Nishiwaki, Y. Hamanaka, Y. Nonogaki, Y. Fujiwara, Y. Takeda, A. Nakamura

Journal of Luminescence 83-84 49 - 53 1999

Language：English Publishing type：Research paper (scientific journal)

We have investigated relaxation dynamics of hot carriers and formation dynamics of excitons in an In0.53Ga0.47As thin film at 4.2 and 77 K by means of femtosecond pump and probe spectroscopy. The spectral change of exciton absorption band induced by the pumping pulse is composed of broadening and peak shift. The broadening is attributed to scattering of excitons created around the Γ point by the probe pulse with free carriers generated by the pumping pulse. The observed blue and red shifts are ascribed to the exciton-exciton exchange interaction and the band-gap renormalization, respectively. The time evolution of the shifts of the order of 30 ps is interpreted in terms of the energy-loss processes of hot carriers with emission of optical phonons. Comparison of the observed decay behaviors with the theoretical calculation, taking into account the Frohlich interaction, indicates a reduction in the carrier cooling rate by a factor of 40 in highly excited In0.53Ga0.47As. © 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0022-2313(99)00073-3

Ultrafast relaxation dynamics of electrons in silver nanocrystals embedded in glass Reviewed

Y. Hamanaka, N. Hayashi, A. Nakamura, and S. Omi

Journal of Luminescence 76&77 221 - 225 1998.04

Language：English Publishing type：Research paper (scientific journal)

Surface plasmon resonance dynamics in silver nanoparticles Reviewed International coauthorship International journal

N. Del Fatti, F. Vallee, C. Flytzanis, Y. Hamanaka, A. Nakamura, and S. Omi

OSA Technical Digest 7 93 - 94 1998

Language：English Publishing type：Research paper (international conference proceedings)

Ultrafast relaxation dynamics of electrons in silver nanocrystals embedded in glass Reviewed

Y. Hamanaka, N. Hayashi, A. Nakamura, S. Omi

Journal of Luminescence 76-77 221 - 225 1998

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier

Relaxation dynamics of excited electrons in silver nanocrystals with average radii of 3.0 and 4.9 nm embedded in glass has been investigated by femtosecond pump and probe spectroscopy. The surface-plasmon band shows both broadening and red shift with excitation by 200 fs laser pulses. Time response exhibits a two-component decay, and the decay times of the fast and slow components are 2-3 ps and ∼ 200 ps, respectively. Time evolution of the nonlinear absorption due to surface-plasmons reflects a cooling process of hot electrons through the electron-phonon interaction. The additional broadening is ascribed to the increase of surface-plasmon damping due to nonequilibrium heating of electrons. When an absolute value of a dielectric constant of silver nanocrystals is decreased with the femtosecond pulse excitation, the surface-plasmon resonance shows a red shift. We demonstrate time response of nonlinear refractive index on the picosecond time scale. © 1998 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0022-2313(97)00205-6

Picosecond dynamics of intramolecular charge-transfer processes of beta-substituted porphyrins adsorbed on the porous glass Reviewed

S. Kotani, H. Miyasaka, A. Itaya, Y. Hamanaka, N. Mataga, S. Nakashima and A. Osuka

Chemical Physics Letters 269 274 - 280 1997.04

Language：English Publishing type：Research paper (scientific journal)

Raman scattering of iodine intercalated C60 crystals Reviewed

S. Nakashima, M. Norimoto, H. Harima, Y. Hamanaka, L. S. Grigoryan and M. Tokumoto

Chemical Physics Letters 268 359 - 364 1997.04

Language：English Publishing type：Research paper (scientific journal)

Temperature dependence of Raman scattering in vapour-grown C60 crystals Reviewed

Y. Hamanaka, M. Norimoto, S. Nakashima, and M. Hangyo

Journal of Physics: Condensed Matter 7 9913 - 9924 1995.04

Language：English Publishing type：Research paper (scientific journal)

Raman scattering of solution-grown and vacuum-deposited C60 crystals Reviewed

Y. Hamanaka, M. Norimoto, S. Nakashima, and M. Hangyo

Chemical Physics Letters 233 590 - 596 1995.04

Language：English Publishing type：Research paper (scientific journal)

Temperature dependence of Raman scattering in vapour-grown C60 crystals Reviewed

Y. Hamanaka, M. Norimoto, S. Nakashima, M. Hangyo

Journal of Physics: Condensed Matter 7 ( 50 ) 9913 - 9924 1995

Language：English Publishing type：Research paper (scientific journal)

The temperature dependence of the Raman spectra of vapour-grown C 60 crystals is investigated with deep-red excitation. The excitation using a deep-red laser can avoid a photo-induced transformation of C 60 crystals during the Raman measurement. It is found that discontinuous changes occur in the Raman spectra at the SC-FCC phase transition temperature (260 K). Most intramolecular vibrational modes broaden drastically as the temperature exceeds 260 K. Crystal-field splitting of the intramolecular vibrational modes is observed below 260 K. The broadening of the Raman bands would be caused by the increase in the inhomogeneity of intermolecular force fields in the FCC phase. This broadening corresponds to the increase in the orientational disorder of C60 molecules above the phase transition.

DOI： 10.1088/0953-8984/7/50/024

X-ray study of phase transition and structure analysis of low temperature phase at 13 K in C60 single crystal Reviewed

H. Kasatani, H. Terauchi, Y. Hamanaka, S. Nakashima, T. Arai, Y. Murakami, and H. Suematsu

Transactions of the Material Research Society of Japan 14B 1267 - 1277 1994.04

Language：English Publishing type：Research paper (scientific journal)

Raman scattering in solid C60 excited by a near-infrared laser Reviewed International journal

Y. Hamanaka, S. Nakashima, and M. Hangyo

Proceedings of the 14th International Conference on Raman Spectroscopy, Hong Kong, 22-26 August, 1994 294 - 295 1994

Authorship：Lead author Language：English Publishing type：Research paper (international conference proceedings)

X-RAY STUDY OF PHASE TRANSITION AND STRUCTURE ANALYSIS OF LOW TEMPERATURE PHASE AT 13K IN C60 SINGLE CRYSTAL Reviewed

H KASATANI, H TERAUCHI, Y HAMANAKA, S NAKASHIMA, T ARAI, Y MURAKAMI, H SUEMATSU

ADVANCED MATERIALS '93, I - A & B 14 ( A & B ) 1267 - 1272 1994

Language：English Publishing type：Research paper (international conference proceedings) Publisher：ELSEVIER SCIENCE PUBL B V

Raman study of a structural phase transition in C60 crystals Reviewed

Y. Hamanaka, S. Nakashima, M. Hangyo, H. Shinohara, and Y. Saito

Physical Review B 48 8510 - 8513 1993.04

Language：English Publishing type：Research paper (scientific journal)

X-ray-diffraction study of the phase transition in a C60 single crystal Reviewed

H. Kasatani, H. Terauchi, Y. Hamanaka, and S. Nakashima

Physical Review B 47 4022 - 4024 1993.04

Language：English Publishing type：Research paper (scientific journal)

Raman study of a structural phase transition in C60 crystals Reviewed

Y. Hamanaka, S. Nakashima, M. Hangyo, H. Shinohara, Y. Saito

Physical Review B 48 ( 11 ) 8510 - 8513 1993

Language：English Publishing type：Research paper (scientific journal)

Raman spectra of purified C60 single crystals are measured over a wide temperature range. It is found that above 400 K the high-frequency Ag mode (pentagonal pinch mode) changes in frequency and becomes sharp compared with the Ag mode at room temperature. This spectral change is reversible. The results indicate that structural change occurs and the intermolecular interaction for each C60 molecule is isotropic above 400 K. A reversible spectral change is observed as the intensity of the excitation laser varies. The similarity between the spectral change at 400 K and the spectral change at high laser intensity levels suggests that the photoinduced spectral change observed in the present study is due to the thermal effects of laser irradiation. © 1993 The American Physical Society.

DOI： 10.1103/PhysRevB.48.8510

X-ray-diffraction study of the phase transition in a C60 single crystal Reviewed

H. Kasatani, H. Terauchi, Y. Hamanaka, S. Nakashima

Physical Review B 47 ( 7 ) 4022 - 4024 1993

Language：English Publishing type：Research paper (scientific journal)

X-ray-diffraction experiments of single-crystal C60 were carried out at temperatures from 300 to 14 K. A small jump in the lattice parameter was observed at the transition temperature TC=260 K, implying that this was a first-order transition. The integrated intensity of the Bragg reflections observed below TC, which corresponded to the order parameter transformed from the orientational disorder state to the orientational order state, was proportional to the anomalous part of the lattice parameter. © 1993 The American Physical Society.

DOI： 10.1103/PhysRevB.47.4022

Time-resolved luminescence spectra of Cr3+ ions in mixed-cation beta-alumina crystals Reviewed

T. Hattori, H. Okamura, and Y. Hamanaka

Key Engineering Materials 59&60 91 - 98 1991.04

Language：English Publishing type：Research paper (scientific journal)

TIME-RESOLVED LUMINESCENCE SPECTRA OF CR-3+ IONS IN MIXED-CATION BETA-ALUMINA CRYSTALS Reviewed

T HATTORI, H OKAMURA, Y HAMANAKA

BETA-ALUMINAS AND BETA-BATTERIES 59 91 - 98 1991

Language：English Publishing type：Research paper (international conference proceedings) Publisher：TRANS TECH PUBLICATIONS