論文 - 安坂　幸師

Ultrahigh porosity photoluminescent silicon aerocrystals with greater than 50% nanocrystal ensemble quantum yields 査読

Bernard Gelloz, Leigh Canham, Koji Asaka, Yuto Nakamura, and Hideo Kishida

Journal of Applied Physics   134   033103   2023年

Self-organized Ge_1−xSn_x quantum dots formed on insulators and their room temperature photoluminescence 査読

Kaoru Hashimoto, Shigehisa Shibayama, Koji Asaka, Mitsuo Sakashita, Masashi Kurosawa, and Osamu Nakatsuka

Japanese Journal of Applied Physics   62   075506   2023年

Solid-phase crystallization of ultra-thin amorphous Ge layers on insulators 査読

Ryo Oishi, Koji Asaka, Leonid Bolotov, Noriyuki Uchida, Masashi Kurosawa, and Osamu Nakatsuka

Japanese Journal of Applied Physics   61   SC1086   2022年

Critical current density for layer-by-layer breakdown of a multiwall carbon nanotube 査読

Koji Asaka, Kentaro Yamauchi, and Yahachi Saito

Diamond and Related Materials   124   108907   2022年

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Electric-current-induced structural changes in a suspended multiwall carbon nanotube (MWCNT) were observed through in-situ transmission electron microscopy. The bias voltage and electric current were measured simultaneously as the MWCNT was imaged. The passage of excessive current led to breakdown of the surface of the MWCNT and to subsequent layer-by-layer removal of the broken outermost shell via sublimation of carbon atoms. The surface breakdown of the MWCNT was accompanied by a discrete decrease in the current. Under the assumption that the current passes solely through the outermost shell of the MWCNT, we found that the critical current densities at which the breakdown in the renewed outermost shell occurred after the removal of the broken outermost shell were limited to a remarkably narrow range of (2.4 ± 0.2)×10⁹ A/cm², irrespective of the outermost diameter of the MWCNT. The present results provide invaluable information about electron transport phenomena in MWCNTs and about the durability of CNT nanocircuits.

Impact of wet annealing on ferroelectric phase formation and phase transition of HfO2-ZrO2 system 査読

Shigehisa Shibayama, Jotaro Nagano, Koji Asaka, Mitsuo Sakashita, and Osamu Nakatsuka

ACS Applied Electronic Materials   3   2203 - 2211   2021年

Hole doping in polythiophenes encapsulated in semiconducting and metallic single-walled carbon nanotubes: Impact of the electronic structure 査読

Hiroto Kageyama, Koji Asaka, Hideo Kishida, and Takeshi Koyama

Macromolecules   54   11147 - 11153   2021年

Light emission and structural changes in a suspended multiwall carbon nanotube on application of electric current 査読

Koji Asaka, Koshi Nishikawa, and Yahachi Saito

Diamond and Related Materials   111   108175   2021年

Raman spectroscopy and TEM of long linear carbon chain formed in CNT field emission cathode 査読

Koji Asaka, Satoshi Toma, and Yahachi Saito

e-Journal of Surface Science and Nanotechnology   18   159 - 163   2020年

Excitation energy transfer by electron exchange via two-step electron transfer between single-walled carbon nanotube and encapsulated magnesium porphyrin 査読

Takeshi Koyama, Junpei Sugiura, Tomonari Koishi, Ryosuke Ohashi, Koji Asaka, Takeshi Saito, Yanlin Gao, Susumu Okada, and Hideo Kishida

The Journal of Physical Chemistry C   124   19406 - 19412   2020年

Application of multiwall carbon nanotubes to conductive manipulation-probe tips for in-situ transmission electron microscopy of nanometer-sized material: Electrical measurement of a silicon nanoparticle 査読

Koji Asaka, Tomohiro Terada, and Yahachi Saito

Materials Research Express   6   015038-1-5   2019年

Raman spectroscopy and transmission electron microscopy study on long linear atomic carbon chains generated by field electron emission accompanied with electrical discharge of carbon nanotube films 査読

Koji Asaka, Satoshi Toma, and Yahachi Saito

SN Applied Sciences   1   493   2019年

Si/SiO2 core/shell luminescent silicon nanocrystals and porous silicon powders with high quantum yield, long lifetime and good stability 査読

Bernard Gelloz, Firman Bagja Juangs, Tomohiro Nozaki, Koji Asaka, Nobuyoshi Koshida, and Lianhua Jin

Frontiers in Physics   7   47-1-7   2019年

Bulk synthesis of linear carbon-chains confined inside single-wall carbon nanotubes by vacuum discharge 査読

Satoshi Toma, Koji Asaka, Masaru Irita, and Yahachi Saito

Surface and Interface Analysis   51   131 - 135   2019年

Different molecular arrangement of perylene in metallic and semiconducting carbon nanotubes: Impact of van der Waals interaction 査読

Takeshi Koyama, Kazuma Fujiki, Yuya Nagasawa, Susumu Okada, Koji Asaka, Yahachi Saito, and Hideo Kishida

The Journal of Physical Chemistry C   122   5805 - 5812   2018年

High-temperature reaction of amorphous silicon with carbon on a multiwall carbon nanotube heater and temperature measurement by thermal radiation spectra 査読

Koji Asaka, Tomohiro Terada, and Yahachi Saito

Journal of Materials Science   52   7232 - 7238   2017年

In-situ TEM study on structural change and light emission of a multiwall carbon nanotube during Joule heating 査読

Koshi Nishikawa, Koji Asaka, Hitoshi Nakahara, and Yahachi Saito

IOP Conference Series: Materials Science and Engineering   304   012011   2017年

Facile synthetic route to atomically thin conductive wires from single-species molecules in one-dimensionally confined space: Doped conjugated polymers inside single-walled carbon nanotubes 査読

Makoto Sasaki, Takeshi Koyama, Hideo Kishida, Koji Asaka, Yahachi Saito, Yukihiro Yoshida, and Gunzi Saito

The Journal of Physical Chemistry Letters   8   1702 - 1706   2017年

Ultrafast excitation energy transfer from encapsulated quaterrylene to single-walled carbon nanotube 査読

Takeshi Koyama, Takuya Tsunekawa, Takeshi Saito, Koji Asaka, Yahachi Saito, Hideo Kishida, and Arao Nakamura

Journal of Luminescence   169   645 - 648   2016年

Spontaneous graphenization of amorphous carbon on clean surfaces of nanometer-sized nickel particles at room temperature 査読

Koji Asaka and Yahachi Saito

Carbon   103   352 - 355   2016年

Field emission patterns showing symmetry of electronic states in graphene edges 査読

Noboru Yokoyama, Kazuya Nakakubo, Kohji Iwata, Koji Asaka, Hitoshi Nakahara, and Yahachi Saito

Surface and Interface Analysis   48   1217 - 1220   2016年

In situ TEM study on structural and electric conduction properties of a multiwall carbon nanotube connected to a Mo electrode 査読

Yuji Shinomiya, Koji Asaka, Hitoshi Nakahara, and Yahachi Saito

Surface and Interface Analysis   48   1206 - 1209   2016年

Structure of amorphous carbon films deposited on Ni nanoparticles under ultrahigh vacuum at room temperature 査読

Koji Asaka and Yahachi Saito

Surface and Interface Analysis   48   1203 - 1205   2016年

アモルファスカーボンの加熱による絶縁基板上へのグラフェン直接形成

長谷部洋平, 安坂幸師, 中原仁, 齋藤弥八

名古屋大学 電子光学研究のあゆみ   ( 25 )   60 - 61   2014年

Transformation of silicon nanoparticles on carbon nanotube heater to hollow graphitic nanocapsules via silicon carbide 査読

Koji Asaka, Tomohiro Terada, and Yahachi Saito

Diamond and Related Materials   50   49 - 54   2014年

Synthesis and photophysics of quaterrylene molecules in single-walled carbon nanotubes: excitation energy transfer between a nanoscale cylinder and encapsulated molecules 査読

Takeshi Koyama, Takuya Tsunekawa, Takeshi Saito, Koji Asaka, Yahachi Saito, Hideo Kishida, and Arao Nakamura

The Journal of Physical Chemistry C   118   21671 - 21681   2014年

In situ TEM study on changes in structure and electrical conductance of carbon nanotube-gold contact induced by local joule heating 査読

Motoyuki Karita, Koji Asaka, Hitoshi Nakahara, and Yahachi Saito

Journal of Materials Science   48   936 - 940   2013年

カーボンナノチューブ表面をテンプレートとするアモルファスカーボンのグラファイト化その場観察

安坂幸師, 苅田基志, 齋藤弥八

名古屋大学 電子光学研究のあゆみ   ( 24 )   15 - 16   2012年

Few-layer epitaxial graphene with large domains on C-terminated 6H-SiC 査読

Hailong Hu, Akkawat Ruammaitree, Hitoshi Nakahara, Koji Asaka, and Yahachi Saito

Surface and Interface Analysis   44   793 - 796   2012年

Study on structure of heat-treated fullerene nanowhiskers and their field electron emission characteristics 査読

Koji Asaka, Tadachika Nakayama, Kun’ichi Miyazawa, and Yahachi Saito

Surface and Interface Analysis   44   780 - 783   2012年

In situ TEM study on the improvement of contact resistance between a carbon nanotube and metal electrodes by local melting 査読

Motoyuki Karita, Koji Asaka, Hitoshi Nakahara, and Yahachi Saito

Surface and Interface Analysis   44   674 - 677   2012年

Evolution of field electron emission pattern from multilayered graphene induced by structural change of edge 査読

Kazuya Nakakubo, Koji Asaka, Hitoshi Nakahara, and Yahachi Saito

Applied Physics Express   5   055101-1-3   2012年

Structures and field emission properties of heat-treated C60 fullerene nanowhiskers 査読

Koji Asaka, Tadachika Nakayama, Kun’ichi Miyazawa, and Yahachi Saito

Carbon   50   1209 - 1215   2012年

Ultrafast energy transfer of one-dimensional excitons between carbon nanotubes: a femtosecond time-resolved luminescence study 査読

Takeshi Koyama, Yasumitsu Miyata, Koji Asaka, Hisanori Shinohara, Yahachi Saito, and Arao Nakamura

Physical Chemistry Chemical Physics   14   1070 - 1084   2012年

ジュール加熱によるカーボンナノチューブと金属の接合過程の透過電子顕微鏡内その場観察

苅田基志, 安坂幸師, 齋藤弥八

名古屋大学 電子光学研究のあゆみ   ( 23 )   45 - 48   2011年

Fabrication of gas field ion emitter by field induced oxygen etching method 査読

Yasushi Sugiura, Huarong Liu, Tatsuo Iwata, Shigekazu Nagai, Kazuo Kajiwara, Koji Asaka, Yahachi Saito, and Koichi Hata

e-Journal of Surface Science and Nanotechnology   9   344 - 347   2011年

Graphitization of amorphous carbon on a multiwall carbon nanotube surface by catalyst-free heating 査読

Koji Asaka, Motoyuki Karita, and Yahachi Saito

Applied Physics Letters   99   091907-1-3   2011年

Chirality assignment to carbon nanotubes integrated in MEMS by tilted-view transmission electron microscopy 査読

Matthias Muoth, Fabian Gramm, Koji Asaka, Lukas Durrer, Thomas Helbling, Cosmin Roman, Shih-Wei Lee, and Chiristofer Hierold

Sensors and Actuators B   154   155 - 159   2011年

Joining of multiwall carbon nanotubes for the end-contact configuration by applying electric current 査読

Koji Asaka, Motoyuki Karita, and Yahachi Saito

Materials Letters   65   1832 - 1834   2011年

Femtosecond luminescence decay due to exciton energy transfer in single-walled carbon nanotube bundles 査読

Takeshi Koyama, Koji Asaka, Naoki Hikosaka, Hideo Kishida, Yahachi Saito, and Arao Nakamura

Journal of Luminescence   131   494 - 497   2011年

Ultrafast exciton energy transfer in bundles of single-walled carbon nanotubes 査読

Takeshi Koyama, Koji Asaka, Naoki Hikosaka, Hideo Kishida, Yahachi Saito, and Arao Nakamura

The Journal of Physical Chemistry Letters   2   127 - 132   2011年

Modification of interface structure and contact resistance between a carbon nanotube and a gold electrode by local melting 査読

Koji Asaka, Motoyuki Karita, and Yahachi Saito

Applied Surface Science   257   2850 - 2853   2011年

Enhancement of third-order optical nonlinearities in carbon nanotubes by encapsulated fullerenes 査読

Daksuke Hosooka, Takeshi Koyama, Hideo Kishida, Koji Asaka, Yahachi Saito, Takeshi Saito, and Arao Nakamura

AIP Conference Proceedings   1399   831 - 832   2011年

Exciton energy transfer between single-walled carbon nanotubes in femtosecond regime 査読

Takeshi Koyama, Koji Asaka, Naoki Hikosaka, Hideo Kishida, Yahachi Saito, and Arao Nakamura

AIP Conference Proceedings   1399   759 - 760   2011年

透過電子顕微鏡内その場観察法によるナノカーボンの構造ダイナミックスと物性

安坂幸師, 齋藤弥八

名古屋大学 電子光学研究のあゆみ   ( 22 )   49 - 52   2010年

Field emission microscopy of Al-deposited carbon nanotubes: emission stability improvement and image of an Al atom cluster 査読

Yahachi Saito, Tomohiro Matsukawa, Koji Asaka, and Hitoshi Nakahara

Journal of Vacuum Science and Technology B   28   C2A5 - C2A8   2010年

Electric and mass transport of a suspended multiwall carbon nanotube studied by in situ transmission electron microscopy 査読

Yasunobu Suzuki, Koji Asaka, Hitoshi Nakahara, and Yahachi Saito

Japanese Journal of Applied Physics   49   02BD07-1-3   2010年

Electric and mass transport of a carbon nanotube encapsulating a copper nano-rod studied by in-situ transmission electron microscopy 査読

Fumitaka Kimura, Koji Asaka, Hitoshi Nakahara, Fumio Kokai, and Yahachi Saito

Journal of Nanoscience and Nanotechnology   10   3907 - 3909   2010年

Tilted-view transmission electron microscopy-access for chirality assignment to carbon nanotubes integrated in MEMS 査読

Matthias Muoth, Fabian Gramm, Koji Asaka, Lukas Durrer, Thomas Helbling, Cosmin Romana, Shih-Wei Lee, and Chiristofer Hierold

Procedia Chemistry   1   601 - 604   2009年

The toughness of multi-wall carbon nanocapsules 査読

Koji Asaka, Kun’ichi Miyazawa, and Tokushi Kizuka

Nanotechnology   20   385705-1-4   2009年

その場電子顕微鏡法によるフラーレンナノウィスカーの構造と物性の研究

加藤良栄, 宮澤薫一, 安坂幸師, 齋藤一真, 木塚徳志

電気学会フィジカルセンサ研究会資料   PHS-08   1 - 4   2008年

Nanowelding of a multiwalled carbon nanotube to metal surface and its electron field emission properties 査読

Koji Asaka, Hitoshi Nakahara, and Yahachi Saito

Applied Physics Letters   92   023114-1-3   2008年

Fracture surface and correlation of buckling force with aspect ratio of C60 crystalline whiskers 査読

Koji Asaka, Ryoei Kato, Ryozo Yoshizaki, Kun’ichi Miyazawa, and Tokushi Kizuka

Diamond and Related Materials   16   1936 - 1939   2007年

Conductance of carbon nanocapsule junctions 査読

Koji Asaka, Ryoei Kato, Ryozo Yoshizaki, Kun’ichi Miyazawa, and Tokushi Kizuka

Physical Review B   76   113404-1-3   2007年

フラーレンナノウィスカー・フラーレンナノチューブの常温合成と物性

宮澤薫一, 湊淳一, 加藤良栄, 安坂幸師, 木塚徳志, 増野匡彦, 中村成夫, 橘 勝, 須賀唯知

電気学会フィジカルセンサ研究会資料   PHS-06   5 - 8   2006年

Deformation of multiwalled nanometer-sized carbon capsules 査読

Koji Asaka, Ryoei Kato, Kun’ichi Miyazawa, and Tokushi Kizuka

Applied Physics Letters   89   191914-1-3   2006年

In situ high-resolution transmission electron microscopy of elastic deformation and fracture of nanometer-sized fullerene C60 whiskers 査読

Ryoei Kato, Koji Asaka, Kun’ichi Miyazawa, and Tokushi Kizuka

Japanese Journal of Applied Physics   45   8024 - 8026   2006年

Buckling of C60 whiskers 査読

Koji Asaka, Ryoei Kato, Kun’ichi Miyazawa, and Tokushi Kizuka

Applied Physics Letters   89   071912-1-3   2006年

Light-emitting filaments composed of nanometer-sized carbon hollow capsules 査読

Koji Asaka, Ryoei Kato, Yoshinari Maezono, Ryozo Yoshizaki, Kun’ichi Miyazawa, and Tokushi Kizuka

Applied Physics Letters   88   051914-1-3   2006年

Measurements of the atomistic mechanics of single crystalline silicon wires of nanometer width 査読

Tokushi Kizuka, Yasuhiro Takatani, Koji Asaka, and Ryozo Yoshizaki

Physical Review B   72   035333-1-6   2005年

Atomistic dynamics of deformation, fracture, and joining of individual single-walled carbon nanotubes 査読

Koji Asaka and Tokushi Kizuka

Physical Review B   72   115431-1-5   2005年

Direct observation of excitonic lasing from single ZnO nanobelts at room temperature 査読

Kazuki Bando, Taiki Sawabe, Koji Asaka, and Yasuaki Masumoto

AIP Conference Proceedings   772   894 - 895   2004年

Room-temperature excitonic lasing from ZnO single nanobelts 査読

Kazuki Bando, Taiki Sawabe, Koji Asaka, and Yasuaki Masumoto

Journal of Luminescence   108   385 - 388   2004年

Transmission electron microscopy and electron diffraction studies on martensitic transformations in nanometer-sized particles of Au-Cd alloys of near-equiatomic compositions 査読

Koji Asaka, Tsugio Tadaki, and Yoshihiko Hirotsu

Philosophical Magazine A   82   463 - 478   2002年

Structure of nanometer-sized Au-Cd alloy particles near equiatomic compositions at room temperature 査読

Koji Asaka, Yoshihiko Hirotsu, and Tsugio Tadaki

Materials Science and Engineering A   312   232 - 236   2001年

Structure and displacive phase transformations of small particles of In-Pb alloys 査読

Koji Asaka, Eri Kitahata, Yoshihiko Hirotsu, Kouichi Kifune, Yoshiki Kubota, and Tsugio Tadaki

Scripta Materialia   44   2043 - 2046   2001年

Au-Cd合金ナノ粒子の変位型一次相変態と格子軟化 査読

安坂幸師, 弘津禎彦, 唯木次男

超微粒子とクラスター懇談会 第4回研究会講演論文集   121 - 124   2000年

Facets of nanometer-sized Fe-Ni alloy particles and their change upon the martensitic transformation 査読

Koji Asaka, Yoshihiko Hirotsu, and Tsugio Tadaki

Materials Science Forum   327-328   409 - 412   2000年

Lattice softening and Its relation to the martensitic transformation in nanometer-sized particles of Fe-Ni alloys 査読

Koji Asaka, Yoshihiko Hirotsu, and Tugio Tadaki

Solid-Solid Phase Transformations, Japan Institute of Metals   Pts1 and 2   1068 - 1071   1999年

Martensitic transformation in nanometer-sized particles of Fe-Ni alloys 査読

Koji Asaka, Yoshihiko Hirotsu, and Tsugio Tadaki

Materials Science and Engineering A   273-275   262 - 265   1999年

Transmission electron microscopy and electron diffraction study on structure and phase transformation of nanometer-sized Fe-15-30 at.% Ni alloy particles 査読

Koji Asaka, Yoshihiko Hirotsu, and Tsugio Tadaki

Journal of Electron Microscopy   48   387 - 391   1999年

Fe-Ni合金ナノ粒子の構造と相変態 査読

安坂幸師, 弘津禎彦, 唯木次男

超微粒子とクラスター懇談会 第2回研究会講演論文集   51 - 54   1998年

TEM and electron diffraction on structure and phase transformation of nanometer-sized Fe-Ni alloy particles 査読

Koji Asaka, Tsugio Tadaki, Yoshihisa Sechi, Bian Bo, Tadakatsu Ohkubo, and Yoshihiko Hirotsu

The Third Pacific Rim International Conference on Advanced Materials and Processing, Minerals, Metals & Materials Society   1   1467 - 1473   1998年