著者

Asaka Koji Kato Ryoei Miyazawa Kun'ichi Kizuka Tokushi

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.89, no.19, pp.191914, 2006-11

被引用文献数

8 10

---

The deformation of isolated multiwalled carbon capsules of a few nanometers in diameter was observed by in situ transmission electron microscopy with simultaneous force measurement by means of an optical cantilever method as used in atomic force microscopy. The mechanical properties of the carbon nanocapsules were investigated on an atomic scale. A carbon nanocapsule of 2.50±0.06 nm in diameter was selected and compressed upto a strain of 0.06 at a force of up to 4.5±0.5 nN using a nanometer-sized gold tip of a microcantilever. By subsequent retraction, we measured the force between the carbon nanocapsule and the gold tip, and assessed the adhesion.

著者

Makimura Tetsuya Uchida Satoshi Murakami Kouichi Niino Hiroyuki

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.89, no.10, pp.101118, 2006-09

被引用文献数

21

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In order to demonstrate silica nanomachining, the authors fabricated line-and-space contact masks with spaces of 53 and 70 nm on silica glass plates, followed by irradiation with laser plasma softx rays (LPSXs) with wavelengths around 10 nm. Trenches with the narrowest width of 54 nm and an aspect ratio of ~1 were fabricated by the LPSX irradiation through the contact masks. It was also clarified that silica glass can be machined by irradiation with LPSXs in the wavelength range of 6–30 nm in Ar gas which was used as an x-ray bandpass filter.

著者

Asaka Koji Kato Ryoei Miyazawa Kun'ichi Kizuka Tokushi

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.89, no.7, pp.071912, 2006-08

被引用文献数

32

---

The authors demonstrated the mechanics of materials for crystalline whiskers composed of C60 molecules; compressive deformation of the whiskers was observed by in situ transmission electron microscopy with simultaneous force measurement by means of an optical cantilever method, as used in atomic force microscopy. In response to compression along the long axis, the whiskers bent first elastically, then buckled. A whisker with 160 nm diameter fractured brittlely at a strain of 0.08. According to Euler's formula, Young's modulus of the whisker was estimated to be 32–54 GPa, which is 160%–650% of that of C60 bulk crystals.

著者

Umeda T. Okonogi K. Ohyu K. Tsukada S. Hamada K. Fujieda S. Mochizuki Y.

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.88, pp.253504, 2006-06

被引用文献数

25 18

---

The variable retention time phenomenon has recently been highlighted as an important issue in dynamic random access memory (DRAM) technology. Based on electrically detected magnetic resonance and simulation studies, we suggest that a single Si vacancy-oxygen complex defect is responsible for this phenomenon, when the defect is embedded in the near surface drain-gate boundary of a DRAM cell.

著者

Paul G. K. Nawa Y. Sato H. Sakurai T. Akimoto K.

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.88, no.14, pp.141901, 2006-04

被引用文献数

88 41

---

Hole traps in p-type Cu2O were studied by means of deep level transient spectroscopy in the heterostructure of p-Cu2O/i-ZnO/n-ZnO. In addition to the trap level at about 0.45 eV from the valance band edge, which is already reported as being due to Cu vacancy, we found a new trap level at about 0.25 eV. The new trap is tentatively assigned as Cu-di-vacancy from the trap concentration dependence on oxygen flow rate and substrate temperature.

著者

Kita Eiji Tsukuhara Naoki Sato Hidenori Ota Keishin Yangaihara Hideto Tanimoto Hisanori Ikeda Naoshi

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.88, pp.152501, 2006-04

被引用文献数

22 19

---

We prepared high-purity oxygen-free and single-phase Ni nanocrystals using the gas condensation and deposition method in order to examine the random anisotropy model (RAM). The grain size of an as-prepared sample was estimated to be 8–10 nm. Thermal annealing increased grain sizes (D) up to 22 nm. Clear D6 dependence of the coercive force on a grain size smaller than 13 nm was obtained for samples prepared on both plastic and KBr single-crystal substrates. For larger grain sizes, Hc decreased with D–1 and these results clearly conform to the RAM in single-element nanocrystal systems. A local anisotropy constant was estimated from the slope of the D6 relation and the peak of Hc at D=13 nm.

著者

Asaka Koji Kato Ryoei Maezono Yoshinari Yoshizaki Ryozo Miyazawa Kun'ichi Kizuka Tokushi

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.88, no.5, pp.051914, 2006-02

被引用文献数

19

---

Filaments composed of multilayered carbon hollow capsules less than 10 nm in diameter have been synthesized from crystalline whiskers of fullerene C60 of submicrometer in diameter by preliminary heating at 1373 K and successive impression of current. The structural, electrical and optical properties of the filaments were studied by in situ transmission electron microscopy combined with the functions of scanning probe microscopy. We found that the filaments easily emit visible light at a maximum wavelength of 700-730 nm by the application of a few volts.

著者

Boero Mauro Oshiyama Atsushi Silvestrelli Pier Luigi Murakami Kouichi

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.86, no.20, pp.201910, 2005-05

被引用文献数

17 18

---

Recent experiments have shown that pure Si structures in a matrix of SiO2 can be formed by electron excitation techniques, with appealing applications in nanotechnology. Our ab initio simulations provide an insight into the underlying mechanism, showing that electron excitations weaken Si–O bonds in SiO2, dislodge O atoms and allow Si dangling bonds to reconstruct in stable Si–Si structures below the melting temperature. Differences in diffusivity of O (fast) and Si (slow) are shown to play a decisive role in the process.

著者

Fukata N. Oshima T. Murakami K. Kizuka T. Tsurui T. Ito S.

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.86, no.21, pp.213112, 2005-05

被引用文献数

79 50

---

A gradual downshift and asymmetric broadening of the Si optical phonon peak were observed by Raman scattering measurements of continuously thermally oxidized silicon nanowires (SiNWs) synthesized by laser ablation. This downshift and broadening can be interpreted by the phonon confinement effect. Further thermal oxidation produced a reverse change; namely, an upshift of the optical phonon peak. This is considered to be due to compressive stress since this stress was relieved by removing the oxide layers formed around the SiNW cores, resulting in a downshift of the optical phonon peak.

著者

Boero Mauro Oshiyama Atsushi Silvestrelli Pier Luigi Murakami Kouichi

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.86, pp.201910, 2005-05

被引用文献数

17

---

Recent experiments have shown that pure Si structures in a matrix of SiO2 can be formed by electron excitation techniques, with appealing applications in nanotechnology. Our ab initio simulations provide an insight into the underlying mechanism, showing that electron excitations weaken Si–O bonds in SiO2, dislodge O atoms and allow Si dangling bonds to reconstruct in stable Si–Si structures below the melting temperature. Differences in diffusivity of O (fast) and Si (slow) are shown to play a decisive role in the process.

著者

Makimura Tetsuya Miyamoto Hisao Kenmotsu Youichi Murakami Kouichi Niino Hiroyuki

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.86, no.10, pp.103111, 2005-03

被引用文献数

38 40

---

We have investigated direct micromachining of quartz glass, using pulsed laser plasma soft x-rays (LPSXs) having a potential capability of nanomachining because the diffraction limit is ~10 nm. The LPSX's were generated by irradiation of a Ta target with 532 nm laser light from a conventional Q switched Nd:YAG laser at 700 mJ/pulse. In order to achieve a sufficient power density of LPSX's beyond the ablation threshold, we developed an ellipsoidal mirror to obtain efficient focusing of LPSXs at around 10 nm. It was found that quartz glass plates are smoothly ablated at 45 nm/shot using the focused and pulsed LPSX's.

著者

Hushur Anwar Shigematsu Hirotake Akishige Yukikuni Kojima Seiji

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.86, no.11, pp.112903, 2005-03

被引用文献数

28 25

---

Ferroelectric single crystals of BaTi2O5 have been studied in detail by Raman and high-resolution micro-Brillouin scattering with a focus on the central component of the relaxation mode over a wide temperature range (20–600 °C). A relaxation mode has been clearly observed in these single crystals. The temperature dependences of the relaxation time and integrated intensity of the relaxation mode are well reproduced by the extended semiclassical tunneling model. The ferroelectric phase transition shows, at least near the vicinity of Tc, an order-disorder nature. Our results indicate that the spontaneous polarization mainly resulted from the dynamic disorder of the Ti ions in the octahedra along the polar b axis of BaTi2O5.

著者

Shabbir Ghulam Ko Jae-Hyeon Kojima Seiji

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.86, no.1, pp.012908, 2004-12

被引用文献数

11 10

---

High-resolution Brillouin scattering experiments have been performed to investigate the low temperature "aging" effect in lanthanum lead zirconate titanate (PLZT) relaxor ferroelectric ceramics. From the temperature dependence of the frequency shift of longitudinal acoustic mode, an acoustic anomaly was observed at T0~46 K in these ceramics with clear "aging" effect below T0. The results have been discussed in the light of stepwise freezing of the related degrees of freedom causing transition from proper to improper dipole glassy states at T0.

著者

Suzuki Kazuya Z. Yanagihara Hideto Niizeki Tomohiko Kojio Ken Kita Eiji

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.101, no.22, pp.222401, 2012-11

被引用文献数

5 4

---

Magnetic and magnetotransport properties of pyromellitic dianhydride-4,4′-oxydianiline polyimide-Co granular thin films prepared by vapor deposition polymerization are investigated. The prepared sample is composed of Co particles with diameters of 2–3 nm homogeneously dispersed in a denatured polyimide matrix. The temperature dependence of the resistivity closely follows the T−1/2 law, suggesting that the dominant conduction mechanism is tunneling between metallic granules embedded in the insulating polyimide matrix. The magnetoresistances at 300 and 90 K are 2.6% and 3.0%, respectively. The results indicate that polyimide is a promising material for organic spintronics.

著者

Makino Kotaro Tominaga Junji Kolobov Alexander V. Fons Paul Hase Muneaki

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.101, no.23, pp.232101, 2012-12

被引用文献数

15

---

We report the optical perturbation of atomic arrangement in the layered in GeTe/Sb2Te3 phase change memory material. To observe the structural change, the coherent A1 mode of GeTe4 local structure was investigated at various polarization angles of femtosecond pump pulses with the fluence at ≤ 78 μJ/cm2. p-polarization found to be more effective in inducing the A1 frequency shift that can be either reversible or irreversible depending on the pump fluence. The predominant origin of this shift is attributed to rearrangement of Ge atoms driven by anisotropic dissociation of the Ge-Te bonds along the [111] axis after the p-polarized pulse irradiation.

著者

Asai Hidehiro Tachiki Masashi Kadowaki Kazuo

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.101, no.11, pp.112602, 2012-09

被引用文献数

23

---

We propose a THz patch antenna, in which THz ac current is fed by intrinsic Josephson junctions (IJJs). The radiation power of the antenna for three different feed positions is calculated using the finite-difference time-domain method. We predict that the antenna will radiate sub-milliwatt terahertz waves with high radiation efficiency of over 20%. The maximum radiation power will depend on the position of the feed. We also show that the radiation characteristics of the antenna are described well by the equivalent inductance-capacitance-resistance circuit model.

著者

Peng D. L. Sumiyama Kenji Yamamuro S. Hihara Takehiko Konno T. J. ヒハラ タケヒコ スミヤマ ケンジ 隅山 兼治 日原 岳彦 Sumiyama K. Hihara T.

出版者

American Institute of Physics

雑誌

APPLIED PHYSICS LETTERS (ISSN:00036951)

巻号頁・発行日

vol.74, no.1, pp.76-78, 1999-01-04

被引用文献数

33

---

We have studied electrical conductivity, σ, and magnetoresistance in a CoO-coated monodispersive Co cluster assembly fabricated by a plasma-gas-aggregation-type cluster beam deposition technique. The temperature dependence of σ is described in the form of log σ vs 1/T for 7<T<80 K. The magnetoresistance ratio (ρ0-ρ3T)/ρ0 increases sharply with decreasing temperature below 25 K: from 3.5% at 25 K to 20.5% at 4.2 K. This marked increase (by a factor of 6) is much larger than those observed for conventional metal-insulator granular systems. These results are ascribed to the Coulomb blockade effect in the monodispersed cluster assemblies.

著者

Toko K. Kurosawa M. Saitoh N. Yoshizawa N. Usami N. Miyao M. Suemasu T.

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.101, no.7, pp.072106, 2012-08

被引用文献数

88 20

---

(111)-oriented Ge thin films on insulators are essential for advanced electronics and photovoltaic applications. We investigate Al-induced crystallization of amorphous-Ge films (50-nm thickness) on insulators focusing on the annealing temperature and the diffusion controlling process between Ge and Al. The (111)-orientation fraction of the grown Ge layer reaches as high as 99% by combining the low-temperature annealing (325 °C) and the native-oxidized Al (AlOx) diffusion-control layer. Moreover, the transmission electron microscopy reveals the absence of defects on the Ge surface. This (111)-oriented Ge on insulators promises to be the high-quality epitaxial template for various functional materials to achieve next-generation devices.

著者

Yamada Yasuhiro Kanemitsu Yoshihiko

出版者

American Institute of Physics

雑誌

Applied Physics Letters (ISSN:00036951)

巻号頁・発行日

vol.101, no.13, 2012-09-27

被引用文献数

232

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二酸化チタン中の光キャリアの振る舞いを解明 -高効率太陽電池の実現に期待-. 京都大学プレスリリース. 2012-09-28.

著者

Suzuki Motofumi Hamachi Kenji Hara Hideki Nakajima Kaoru Kimura Kenji Hsu Chia-Wei Chou Li-Jen

出版者

American Institute of Physics

雑誌

Applied Physics Letters (ISSN:00036951)

巻号頁・発行日

vol.99, no.22, 2011-12

被引用文献数

13

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We have demonstrated that the vapor-liquid-solid (VLS) growth of Ge nanowhiskers is significantly enhanced by high-temperature glancing angle deposition (HT-GLAD). At the substrate temperature of 420 °C, the Ge nanowhiskers grow on the sample deposited at the deposition angle of α = 85°, whereas no long nanowhisker grows on the samples deposited at α ≤ 73°. The kinetic growth model that takes into account the directional incidence of the vapor flux agrees with the experimental results and suggests that the atoms deposited on the side surface of the nanowhiskers play an essential role in the HT-GLAD assisted VLS growth. Supplying the atoms on the side surface of the nanowhiskers is expected to accelerate the growth of the nanowhiskers in any vapor phase growth methods, such as molecular beam epitaxy and chemical vapor deposition.