Faculty Profiles - OHNO, Yutaka

Papers - OHNO, Yutaka

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Dry and Direct Deposition of Aerosol-Synthesized Single-Walled Carbon Nanotubes by Thermophoresis

Laiho Patrik, Mustonen Kimmo, Ohno Yutaka, Maruyama Shigeo, Kauppinen Esko I.

ACS APPLIED MATERIALS & INTERFACES Vol. 9 ( 24 ) page： 20738 - 20747 2017.6

Purification of 1.9-nm-diameter semiconducting single-wall carbon nanotubes by temperature-controlled gel-column chromatography and its application to thin-film transistor devices Open Access

Thendie Boanerges, Omachi Haruka, Hirotani Jun, Ohno Yutaka, Miyata Yasumitsu, Shinohara Hisanori

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 56 ( 6 ) 2017.6

Adaptive Control of Angular Sensitivity for VHF-Band Nano-Antenna Using CNT Mechanical Resonator

Tanaka H., Ohno Y., Tadokoro Y.

IEEE Transactions on Molecular, Biological, and Multi-Scale Communications Vol. 3 ( 1 ) page： 24 - 32 2017.3

Language：Japanese Publisher：IEEE Transactions on Molecular, Biological, and Multi-Scale Communications

An adaptive control method of angular sensitivity for a VHF-band nano-antenna is presented. This antenna is composed of a single carbon nanotube cantilever immersed in a DC electric field. The behavior of the antenna is analytically described using a singly clamped metallic sphere model and the image charge method. We derive design guidelines for the direction and shape of angular sensitivity; the amplitude of the DC electric field is a key parameter for controlling the sensitivity. The analysis reveals that the most sensitive direction is tunable in the range of -π/2 to π/2. The shape of sensitivity can be manipulated to be omnidirectional or to correspond to a Hertzian-dipole-like antenna. This investigation is useful for adaptive control to suppress interference signals in nanoscale communication systems.

DOI： 10.1109/TMBMC.2016.2640282

Scopus

Angular Sensitivity Steering in CNT Electromagnetic Wave Detector

Nobunaga Tatsuya, Tadokoro Yukihiro, Ohno Yutaka, Tanaka Hiroya

IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS Vol. 16 page： 1405 - 1408 2017

Origin of residual particles on transferred graphene grown by CVD Reviewed

Yasunishi Tomohiro, Takabayashi Yuya, Kishimoto Shigeru, Kitaura Ryo, Shinohara Hisanori, Ohno Yutaka

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 55 ( 8 ) 2016.8

Highly individual SWCNTs for high performance thin film electronics Open Access

Kaskela Antti, Laiho Patrik, Fukaya Norihiro, Mustonen Kimmo, Susi Toma, Jiang Hua, Houbenov Nikolay, Ohno Yutaka, Kauppinen Esko I.

CARBON Vol. 103 page： 228 - 234 2016.7

Language：Japanese Publisher：Carbon

We report a continuous floating catalyst chemical vapor deposition synthesis of highly individual single-walled carbon nanotubes (SWCNT) for high performance transparent conducting films (TCF). Active feedback dilution of ferrocene-based catalyst vapor leads to an almost complete elimination of SWCNT bundling and a substantial increase in SWCNT lengths via the suppression of bundling-induced growth termination. The fabricated uniform TCFs exhibit sheet resistances of 89 Ω/sq. at 90% transmittance. This was further improved by micro-patterning, resulting in a sheet resistance of 69 Ω/sq. at 97% transmittance - the highest reported for any carbon nanotube TCF - and highly competitive with commercial indium-tin-oxide-TCFs. Furthermore, we demonstrate that thin film transistors fabricated from these highly individual SWCNTs reach charge carrier mobilities up to 100 cm2 V-1s-1 and ON/OFF-ratios up to 106.

DOI： 10.1016/j.carbon.2016.02.099

Web of Science

Scopus

Highly stable perovskite solar cells with an all-carbon hole transport layer

Wang Feijiu, Endo Masaru, Mouri Shinichiro, Miyauchi Yuhei, Ohno Yutaka, Wakamiya Atsushi, Murata Yasujiro, Matsuda Kazunari

NANOSCALE Vol. 8 ( 23 ) page： 11882 - 11888 2016

Language：Japanese Publisher：Nanoscale

Nano-carbon materials (carbon nanotubes, graphene, and graphene oxide) have potential application for photovoltaics because of their excellent optical and electronic properties. Here, we demonstrate that a single-walled carbon nanotubes/graphene oxide buffer layer greatly improves the photovoltaic performance of organo-lead iodide perovskite solar cells. The carbon nanotubes/graphene oxide buffer layer works as an efficient hole transport/electron blocking layer. The photovoltaic conversion efficiency of 13.3% was achieved in the organo-lead iodide perovskite solar cell due to the complementary properties of carbon nanotubes and graphene oxide. Furthermore, the great improvement of photovoltaic performance stability in the perovskite solar cells using carbon nanotubes/graphene oxide/polymethyl methacrylate was demonstrated in comparison with that using a typical organic hole transport layer of 2,2′,7,7′-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9′-spirobifluorene.

DOI： 10.1039/c6nr01152g

Web of Science

Scopus

PubMed

Toward the Limits of Uniformity of Mixed Metallicity SWCNT TFT Arrays with Spark-Synthesized and Surface-Density-Controlled Nanotube Networks Reviewed

Kaskela Antti, Mustonen Kimmo, Laiho Patrik, Ohno Yutaka, Kauppinen Esko I.

ACS APPLIED MATERIALS & INTERFACES Vol. 7 ( 51 ) page： 28134 - 28141 2015.12

Angular Sensitivity of VHF-Band CNT Antenna Reviewed

Tanaka Hiroya, Ohno Yutaka, Tadokoro Yukihiro

IEEE TRANSACTIONS ON NANOTECHNOLOGY Vol. 14 ( 6 ) page： 1112 - 1116 2015.11

Overcoming the quality-quantity tradeoff in dispersion and printing of carbon nanotubes by a repetitive dispersion-extraction process Reviewed Open Access

Shirae Hiroyuki, Kim Dong Young, Hasegawa Kei, Takenobu Taishi, Ohno Yutaka, Noda Suguru

CARBON Vol. 91 page： 20 - 29 2015.9

Printed, short-channel, top-gate carbon nanotube thin-film transistors on flexible plastic film

Maeda Michihiko, Hirotani Jun, Matsui Ryotaro, Higuchi Kentaro, Kishimoto Shigeru, Tomura Takuya, Takesue Masafumi, Hata Katsuhiko, Ohno Yutaka

APPLIED PHYSICS EXPRESS Vol. 8 ( 4 ) 2015.4

Transparent, flexible all-carbon electron devices Reviewed

OHNO Yutaka

Oyo Buturi Vol. 84 ( 2 ) page： 142 - 145 2015.2

Language：Japanese Publisher：The Japan Society of Applied Physics

<p>Carbon nanotube (CNT) thin films are rare materials with multi-functionality in addition to superior electric, optical and mechanical characteristics. This article introduces all-carbon devices having a semiconductor layer and electrodes, with wiring made of a CNT thin film. They are flexible and transparent as well as having the ability to be thermoformed into a variety of 3D shapes. Taking advantage of these characteristics allows the realization of unobservable devices or 3D or highly designable devices.</p>

DOI： 10.11470/oubutsu.84.2_142

CiNii Research

Electroluminescence from an Electrostatically Doped Carbon Nanotube Field-Effect Transistor Open Access

Hughes M. A., Ohno Y., Mizutani T.

NANOSCIENCE AND NANOTECHNOLOGY LETTERS Vol. 6 ( 10 ) page： 881 - 886 2014.10

Language：Japanese Publisher：Nanoscience and Nanotechnology Letters

We report electroluminescence (EL) from a carbon nanotube field-effect transistor with split-gates. EL is generated by the electrostatic doping technique. Six EL bands could be observed, with the strongest band peaking between 0.867 and 0.850 eV with a full width at half maximum (FWHM) of 64 to 120 meV, depending on the bias conditions. From the EL peak position we estimate a CNT diameter of ∼ 1.05 nm. We also estimate the power and quantum efficiency of the EL to be around 1 × 10-6and 1 × 10-5 respectively. With a fixed drain voltage, increasing the opposite split gate bias caused the EL to increase monotonically from zero, indicating an ambipolar emission mechanism. With a fixed opposite split gate bias the dependence of EL on drain voltage displays a threshold. Drain current is significantly higher when using equal, rather than opposite split gate biases, which we attribute to the trapping of carries by band bending when using opposite split gate bias.

DOI： 10.1166/nnl.2014.1831

Web of Science

Scopus

Photocurrent from a carbon nanotube diode with split-gate and asymmetric contact geometry Open Access

Hughes M. A., Homewood K. P., Curry R. J., Ohno Y., Mizutani T.

MATERIALS RESEARCH EXPRESS Vol. 1 ( 2 ) 2014.6

Language：Japanese Publisher：Materials Research Express

We fabricated a Ti/Pd asymmetrically contacted single carbon nanotube (CNT) field-effect transistor (FET) with split-gates. Transfer characteristics can be explained if the Schottky barrier for electrons is lower at the Pd contact than it is at the Ti contact. Strong rectification is observed when the gates are unbiased, and the rectification direction can be inverted with the appropriate gate bias. When operated as an FET the device has an on/off ratio of 1 × 107. Under illumination, photocurrent can only be observed with opposite split-gate bias. Open circuit voltage (VOC) and short circuit current (ISC) increase with increasing opposite polarity split-gate bias, representing the first demonstration of the modulation of VOC and ISC in an asymmetric contact CNT FET.

DOI： 10.1088/2053-1591/1/2/026304

Web of Science

Scopus

Effect of ambient air on n-type carbon nanotube thin-film transistors chemically doped with poly(ethylene imine)

Yasunishi Tomohiro, Kishimoto Shigeru, Ohno Yutaka

JAPANESE JOURNAL OF APPLIED PHYSICS Vol. 53 ( 5 ) 2014.5

Fabrication of Single-Walled Carbon Nanotube/Si Heterojunction Solar Cells with High Photovoltaic Performance

Wang Feijiu, Kozawa Daichi, Miyauchi Yuhei, Hiraoka Kazushi, Mouri Shinichiro, Ohno Yutaka, Matsuda Kazunari

ACS PHOTONICS Vol. 1 ( 4 ) page： 360 - 364 2014.4

One-Step Sub-10 mu m patterning of Carbon-Nanotube Thin Films for Transparent Conductor Applications

Fukaya Norihiro, Kim Dong Young, Kishimoto Shigeru, Noda Suguru, Ohno Yutaka

ACS NANO Vol. 8 ( 4 ) page： 3285 - 3293 2014.4

Split gate and asymmetric contact carbon nanotube optical devices Open Access

Hughes M. A., Homewood K. P., Curry R. J., Ohno Y., Mizutani T.

OPTICAL COMPONENTS AND MATERIALS XI Vol. 8982 2014

Language：Japanese Publisher：Proceedings of SPIE - The International Society for Optical Engineering

Asymmetric contacts or split gate geometries can be used to obtain rectification, electroluminescence (EL) and photocurrent from carbon nanotube field effect transistors. Here, we report devices with both split gates and asymmetric contacts and show that device parameters can be optimised with an appropriate split gate bias, giving the ability to select the rectification direction, modify the reverse bias saturation current and the ideality factor. When operated as a photodiode, the short circuit current and open circuit voltage can be modified by the split gate bias, and the estimated power conversion efficiency was 1×10-6. When using split gates and symmetric contacts, strong EL peaking at 0.86 eV was observed with a full width at half maximum varying between 64 and 120 meV, depending on the bias configuration. The power and quantum efficiency of the EL was estimated to be around 1×10-6 and 1×10-5 respectively.

DOI： 10.1117/12.2036962

Web of Science

Scopus

True Nanoの世界：カーボンナノチューブ：特異な物性を活かした電子デバイス Reviewed

大野雄高

パリティ Vol. 29 page： 18 - 21 2014

Carbon nanotube-based thin-film transistors on plastic film

Ohno Y.

Proceedings of the 20th International Workshop on Active-Matrix Flatpanel Displays and Devices: TFT Technologies and FPD Materials, AM-FPD 2013 page： 243 - 246 2013.11

Language：Japanese Publisher：Proceedings of the 20th International Workshop on Active-Matrix Flatpanel Displays and Devices: TFT Technologies and FPD Materials, AM-FPD 2013

Among various kinds of semiconductor materials, carbon nanotubes can provide high-mobility, low-operation voltage, flexible devices on plastic films at low cost. High-mobility thin-film transistors (TFTs) and functional integrated circuits (ICs) have been fabricated by simple transfer process on a transparent plastic substrate. All-carbon ICs have also been realized for the first time, which has better transparency, flexibility, and stretchability. We also demonstrate high-throughput printing fabrication of high-mobility TFT arrays with flexographic printing technique. © 2013 JSAP.

Scopus

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Papers - OHNO, Yutaka