Faculty Profiles - OHNO, Yutaka

Papers - OHNO, Yutaka

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Fabrication and Characterization of Peapod Field-Effect Transistors Using Peapods Synthesized Directly on Si Substrate

Kurokawa Yuto, Ohno Yutaka, Shimada Takashi, Ishida Masashi, Kishimoto Shigeru, Okazaki Toshiya, Shinohara Hisanori, Mizutani Takashi

Japanese Journal of Applied Physics Vol. 44 ( 42-45 ) page： L1341 - L1343 2005

Language：Japanese Publisher：The Japan Society of Applied Physics

We have successfully fabricated carbon nanopeapod field-effect transistors (FETs) using peapods synthesized directly on a SiO2/Si substrate. Single-walled carbon nanotubes (SWNTs) for pods were synthesized on the substrate by utilizing position-controlled chemical vapor deposition. The end caps of the SWNTs were removed by oxidation by baking in air. Insertion of fullerenes into the cap-opened SWNTs was performed by the vapor phase doping method. Fabricated Gd@C82 peapod FETs showed ambipolar characteristics. We have estimated the bandgap of the Gd@C82 peapod to be ∼100 meV from the temperature dependence of the drain current.

DOI： 10.1143/JJAP.44.L1341

Web of Science

Scopus

CiNii Research

Fabrication and characterization of carbon nanotube FETs

Mizutani T, Ohno Y

QUANTUM SENSING AND NANOPHOTONIC DEVICES II Vol. 5732 page： 28 - 36 2005

Origin of the 2450 cm(-1) Raman bands in HOPG, single-wall and double-wall carbon nanotubes

Shimada T, Sugai T, Fantini C, Souza M, Cancado LG, Jorio A, Pimenta MA, Salto R, Gruneis A, Dresselhaus G, Dresselhaus MS, Ohno Y, Mizutani T, Shinohara H

CARBON Vol. 43 ( 5 ) page： 1049 - 1054 2005

Surface potential transient of AlGaN/GaN HEMTs measured by Kelvin probe force microscopy

Nakagami K, Ohno Y, Kishimoto S, Maezawa K, Mizutani T

COMPOUND SEMICONDUCTORS 2004, PROCEEDINGS Vol. 184 page： 275 - 278 2005

Surface potential measurements of AlGaN/GaN high-electron-mobility transistors by Kelvin probe force microscopy

Nakagami K, Ohno Y, Kishimoto S, Maezawa K, Mizutani T

APPLIED PHYSICS LETTERS Vol. 85 ( 24 ) page： 6028 - 6029 2004.12

Fluid Dynamic Assembly of Semiconductor Blocks for Heterogeneous Integration

Soga Ikuo, Ohno Yutaka, Kishimoto Shigeru, Maezawa Koichi, Mizutani Takashi

Japanese Journal of Applied Physics Vol. 43 ( 9A ) page： 5951 - 5954 2004.9

Language：Japanese Publisher：The Japan Society of Applied Physics

We have studied the fluidic assembly (FA) technique for heterogeneous integration. In this technique, device blocks, the size of which ranges from a few tens of microns to a few hundreds of microns, are arranged onto another material substrate in fluid. Here, we propose a novel technique to improve FA, called fluid dynamic assembly (FDA), which employs fluid dynamic effects. In the FDA, a special structure is fabricated on the block, which stabilizes the posture of the blocks falling in the fluid. This can be used to control the face of assembled blocks. In this paper, the feasibility of the FDA is discussed on the basis of fluid dynamic simulation and experiments. The numerical simulations revealed that the face control can be carried out for the block having ringlike (O-type) structures on it. Then we carried out the FDA experiments using thin disk-shaped GaAs blocks with O-type structure, and demonstrated an 87% face control ratio for the blocks with 7.5-μm-thick structure. Moreover, the less symmetric C-type structure was examined, and demonstrated even a high face control ratio of 96%.

DOI： 10.1143/JJAP.43.5951

Web of Science

CiNii Research

Direct Observation of High-Frequency Chaos Signals from the Resonant Tunneling Chaos Generator

Maezawa Koichi, Kawano Yoichi, Ohno Yutaka, Kishimoto Shigeru, Mizutani Takashi

Japanese Journal of Applied Physics Vol. 43 ( 8A ) page： 5235 - 5238 2004.8

Language：Japanese Publisher：The Japan Society of Applied Physics

The direct observation of the chaos signal patterns in a microwave frequency range was demonstrated on the resonant tunneling chaos generator circuit. It is difficult to observe such high-frequency chaos because one must use a sampling oscilloscope. To overcome this problem, we devised a special circuit controlling the chaos to output identical signals repeatedly. This permits us to observe (seemingly)random patterns. This control scheme may lead to various applications.

DOI： 10.1143/jjap.43.5235

Web of Science

CiNii Research

Fabrication Technique for Carbon Nanotube Single-Electron Transistors Using Focused Ion Beam

Kurokawa Yuto, Ohno Yutaka, Kishimoto Shigeru, Okazaki Toshiya, Shinohara Hisanori, Mizutani Takashi

Japanese Journal of Applied Physics Vol. 43 ( 8A ) page： 5669 - 5670 2004.8

Language：Japanese Publisher：The Japan Society of Applied Physics

We have proposed a technique for fabricating carbon nanotube single-electron transistors using a focused ion beam (FIB). Wiring to a multiwalled carbon nanotube was formed by the ion-beam-assisted deposition of tungsten. Tunneling barriers were formed in the nanotube by ion beam etching. A drain current oscillation originating from the Coulomb blockade effect was observed at 23 K.

DOI： 10.1143/JJAP.43.5669

Web of Science

CiNii Research

Drain current DLTS of AlGaN-GaN MIS-HEMTs

Okino T, Ochiai A, Ohno Y, Kishimoto S, Maezawa K, Mizutani I

IEEE ELECTRON DEVICE LETTERS Vol. 25 ( 8 ) page： 523 - 525 2004.8

Double-wall carbon nanotube field-effect transistors: Ambipolar transport characteristics

Shimada T, Sugai T, Ohno Y, Kishimoto S, Mizutani T, Yoshida H, Okazaki T, Shinohara H

APPLIED PHYSICS LETTERS Vol. 84 ( 13 ) page： 2412 - 2414 2004.3

Effects of surface passivation on breakdown of AlGaN/GaN high-electron-mobility transistors

Ohno Y, Nakao T, Kishimoto S, Maezawa K, Mizutani T

APPLIED PHYSICS LETTERS Vol. 84 ( 12 ) page： 2184 - 2186 2004.3

Transport properties of C-78, C-90 and Dy@C-82 fullerenes-nanopeapods by field effect transistors

Shimada T, Ohno Y, Okazaki T, Sugai T, Suenaga K, Kishimoto S, Mizutani T, Inoue T, Taniguchi R, Fukui N, Okubo H, Shinohara H

PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES Vol. 21 ( 2-4 ) page： 1089 - 1092 2004.3

Chirality assignment of individual single-walled carbon nanotubes in carbon nanotube field-effect transistors by micro-photocurrent spectroscopy

Ohno Y, Kishimoto S, Mizutani T, Okazaki T, Shinohara H

APPLIED PHYSICS LETTERS Vol. 84 ( 8 ) page： 1368 - 1370 2004.2

Drain current DLTS of AlGaN/GaN HEMTs

Mizutani T, Okino T, Kawada K, Ohno Y, Kishimoto S, Maezawa K

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE Vol. 200 ( 1 ) page： 195 - 198 2003.11

Fabricated on a GaAs-based Semiconductor-on-Insulator Substrate Using a Spin-On Low-k Dielectric Film

Sato Kuninori, Ohno Yutaka, Kishimoto Shigeru, Maezawa Koichi, Mizutani Takashi

Japanese Journal of Applied Physics Vol. 42 ( 11 ) page： 6839 - 6840 2003.11

Language：Japanese Publisher：The Japan Society of Applied Physics

We proposed and successfully fabricated a GaAs-based semiconductor-on-insulator (SOI) metal–semiconductor-filed-effect-transistor (MESFET) using a low-temperature wafer-bonding technique with a spin-on low-k dielectric film, FOx, as a bonding layer. In this structure, the channel is isolated from the semi-insulating (SI) GaAs substrate by a FOx layer. The fabricated 1-μm-gate-length SOI MESFETs showed good pinch-off and saturation characteristics. One of the most important improvements expected for this structure is a reduction of the drain-source capacitance, CDS, which dominates the microwave switching property (on/off ratio). It was demonstrated that the CDS of the SOI MESFET is much smaller than that of the conventional GaAs MESFET. It was also confirmed that the drain current of the SOI MESFET is negligibly affected by the side-gate voltage.

DOI： 10.1143/JJAP.42.6839

Web of Science

CiNii Research

Experimental Demonstration of Capacitor-Coupled Resonant Tunneling Logic Gates for Ultra-short Gate-delay Operation

Tanaka Tetsuro, Ohno Yutaka, Kishimoto Shigeru, Maezawa Koichi, Mizutani Takashi

Japanese Journal of Applied Physics Vol. 42 ( 11 ) page： 6766 - 6771 2003.11

Language：Japanese Publisher：The Japan Society of Applied Physics

The capacitor-coupled monostable-bistable transition logic element (C2MOBILE) is an extension of the high-speed logic gate MOBILE based on the negative differential resistance of the resonant tunneling diodes. The C2MOBILE uses a transient current through the coupling capacitor to transmit signals between gates, and is expected to operate with an extremely short gate delay time. In this paper, basic operations of the C2MOBILE are demonstrated with the circuits fabricated on InP substrates. The circuits tested here are the 2- and 3-stage logic circuits and the AND/OR gate. The gate delay time was estimated to be around 1 ps for these circuits. A much shorter gate delay time close to 100 fs should be possible with the sophisticated circuit design and fabrication process.

DOI： 10.1143/JJAP.42.6766

Web of Science

CiNii Research

88 GHz dynamic 2 : 1 frequency divider using resonant tunnelling chaos circuit

Kawano Y, Ohno Y, Kishimoto S, Maezawa K, Mizutani T, Sano K

ELECTRONICS LETTERS Vol. 39 ( 21 ) page： 1546 - 1548 2003.10

A study on current collapse in AlGaN/GaN HEMTs induced by bias stress

Mizutani T, Ohno Y, Akita M, Kishimoto S, Maezawa K

IEEE TRANSACTIONS ON ELECTRON DEVICES Vol. 50 ( 10 ) page： 2015 - 2020 2003.10

Position-Controlled Carbon Nanotube Field-Effect Transistors Fabricated by Chemical Vapor Deposition Using Patterned Metal Catalyst

Ohno Yutaka, Iwatsuki Shinya, Hiraoka Tatsuki, Okazaki Toshiya, Kishimoto Shigeru, Maezawa Koichi, Shinohara Hisanori, Mizutani Takashi

Japanese Journal of Applied Physics Vol. 42 ( 6B ) page： 4116 - 4119 2003.6

Language：Japanese Publisher：The Japan Society of Applied Physics

Position-controlled carbon nanotube field effect transistors (FETs) have been fabricated by using patterned catalysts and chemical vapor deposition. A double-layer metal of platinum and cobalt was used as the catalyst. The use of a mixture of ethanol and argon as the source gas was effective for obtaining FETs with good characteristics. Coulomb oscillation was observed at room temperature. 76% of the fabricated devices showed FET operation. The characteristics of FETs with metallic nanotubes were improved by applying a high voltage.

DOI： 10.1143/JJAP.42.4116

Web of Science

CiNii Research

AlGaN/GaN Heterostructure Metal-Insulator-Semiconductor High-Electron-Mobility Transistors with Si3N4 Gate Insulator

Ochiai Masaru, Akita Mitsutoshi, Ohno Yutaka, Kishimoto Shigeru, Maezawa Kouichi, Mizutani Takashi

Japanese Journal of Applied Physics Vol. 42 ( 4B ) page： 2278 - 2280 2003.4

Language：Japanese Publisher：The Japan Society of Applied Physics

AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) using Si3N4 film as a gate insulator have been successfully fabricated. The gate leakage current decreased by about three orders of magnitude compared to that of the conventional AlGaN/GaN HEMTs without the Si3N4 gate insulator. The low-frequency noise of the MIS-HEMTs was smaller than that of the conventional HEMTs. Current collapse has also been suppressed in the MIS-HEMTs.

DOI： 10.1143/JJAP.42.2278

Web of Science

CiNii Research

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Papers - OHNO, Yutaka