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396 results on '"Endo, Katsuyoshi"'

4. First-principles study of tunnel current between scanning tunneling microscopy tip and hydrogen-adsorbed Si(001) surface

Author

Ono, Tomoya, Horie, Shinya, Endo, Katsuyoshi, and Hirose, Kikuji

Subjects
Condensed Matter - Materials Science
Abstract

A scanning tunneling microscopy (STM) image of a hydrogen-adsorbed Si(001) surface is studied using first-principles electron-conduction calculation. The resultant STM image and scanning tunneling spectroscopy spectra are in agreement with experimental results. The contributions of the $\pi$ states of bare dimers to the tunnel current are markedly large, and the $\sigma$ states of the dimers rarely affect the STM images. The tunnel currents do not pass through the centers of the dimers but go through the edges of the dimers with local loop currents. In addition, when the tip exists above the hydrogen-adsorbed dimer, there are certain contributions from the $\pi$ state of the adjacing bare dimers to the tunnel current. This leads to the STM image in which the hydrogen-adsorbed dimers neighboring bare dimers look higher than those surrounded by hydrogen-adsorbed dimers. These results are consistent with the experimental images observed by STM., Comment: 10 pages and 4 figures

Published
2006
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5. First-principles study on scanning tunneling microscopy images of hydrogen-terminated Si(110) surfaces

Author

Horie, Shinya, Arima, Kenta, Hirose, Kikuji, Katoh, Jun, Ono, Tomoya, and Endo, Katsuyoshi

Subjects
Condensed Matter - Materials Science
Abstract

Scanning tunneling microscopy images of hydrogen-terminated Si(110) surfaces are studied using first-principles calculations. Our results show that the calculated filled-state images and local density of states are consistent with recent experimental results, and the empty-state images appear significantly different from the filled-state ones. To elucidate the origin of this difference, we examined in detail the local density of states, which affects the images, and found that the bonding and antibonding states of surface silicon atoms largely affect the difference between the filled- and empty-state images., Comment: 4 pages, and 4 figures

Published
2005
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34. Surface Modification of Fluoropolymer Using Open-Air Plasma Treatment at Atmospheric Pressure with Ar, Ar＋O2, and Ar＋H2 for Application in HighAdhesion Metal Wiring Patterns

Author

Kodama, Yoshinori, Ohkubo, Yuji, Oshita, Takaya, Nakano, Yoshinori, Uehara, Tsuyoshi, Aoyama, Teppei, Endo, Katsuyoshi, and Yamamura, Kazuya

Subjects
Polytetrafluoroethylene (PTFE), Atmospheric Plasma Treatment, Adhesion, Ag Ink, Printed Circuit Board for High-Frequency
Abstract

We performed open-air plasma treatment of polytetrafluoroethylene (PTFE) at atmospheric pressure to increase the adhesion strength between PTFE and an Ag metal film formed from Ag ink. Coloration of the PTFE surface occurred during 600 s treatment with Ar plasma. The Ag/PTFE adhesion strength was 0.06 N/mm. To resolve the problem of coloration and to improve the adhesion strength, O2 or H2 gas was added. During treatment with Ar+O2 plasma with O2 content of 0.33% for 600 s, no coloration occurred but the adhesion strength decreased to zero. During treatment with Ar+H2 plasma for 600 s, coloration did not occur. Moreover, the adhesion strength increased to 0.25-0.55 N/mm. These results showed that H2 addition was effective for preventing coloration and improving adhesion strength during long-period plasma treatment. Furthermore, the uniformity of surface treatment with Ar+H2 plasma was higher than that for Ar plasma.

Published
2018

36. Hydrogen termination of Si(110) surfaces upon wet cleaning revealed by highly resolved scanning tunneling microscopy

Author

Arima, Kenta, Katoh, Jun, Ono, Tomoya, Horie, Shinya, Endo, Katsuyoshi, Sugawa, Shigetoshi, Akahori, Hiroshi, Teramoto, Akinobu, and Ohmi, Tadahiro

Subjects
Scanning tunneling microscopy -- Usage, Hydrogen -- Structure, Hydrogen -- Atomic properties, Silicon -- Structure, Silicon -- Atomic properties, Physics
Abstract

The surface structure of the hydrogen-saturated Si(110) surfaces after wet cleaning is studied on an atomic scale by using scanning tunneling microscopy. The mechanism underlying the formation of the hydrogen-terminated Si(110) surfaces during wet cleaning processes is obtained from the results.

Published
2005

37. Wave-optical evaluation of interference fringes and wavefront phase in a hard-x-ray beam totally reflected by mirror optics

Author

Yamauchi, Kazuto, Yamamura, Kazuya, Mimura, Hidekazu, Sano, Yasuhisa, Saito, Akira, Endo, Katsuyoshi, Souvorov, Alexei, Yabashi, Makina, Tamasaku, Kenji, Ishikawa, Tetsuya, and Mori, Yuzo

Subjects
Optics -- Research, X-rays -- Research, Astronomy, Physics
Abstract

The intensity flatness and wavefront shape in a coherent hard-x-ray beam totally reflected by flat mirrors that have surface bumps modeled by Gaussian functions were investigated by use of a wave-optical simulation code. Simulated results revealed the necessity for peak-to- valley height accuracy of better than 1 nm at a lateral resolution near 0.1 mm to remove high-contrast interference fringes and appreciable wavefront phase errors. Three mirrors that had different surface qualities were tested at the 1 km-long beam line at the SPring-8/Japan Synchrotron Radiation Research Institute. Interference fringes faded when the surface figure was corrected below the subnanometer level to a spatial resolution close to 0.1 mm, as indicated by the simulated results. OCIS codes: 340.7470, 340.6720, 220.4610, 220.4840, 220.5450.

Published
2005

41. Creation of perfect surfaces

Author

Mori, Yuzo, Yamamura, Kazuya, Endo, Katsuyoshi, Yamauchi, Kazuto, Yasutake, Kiyoshi, Goto, Hidekazu, Kakiuchi, Hiroaki, Sano, Yasuhisa, and Mimura, Hidekazu

Published
2005
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48. Influence of air contamination during heat-assisted plasma treatment on adhesion properties of polytetrafluoroethylene (PTFE)

Author

1000010525786, Ohkubo, Yuji, Nakagawa, Tetsuya, 1000090152008, Endo, Katsuyoshi, 1000060240074, Yamamura, Kazuya, 1000010525786, Ohkubo, Yuji, Nakagawa, Tetsuya, 1000090152008, Endo, Katsuyoshi, 1000060240074, and Yamamura, Kazuya

Abstract

Ohkubo Y., Nakagawa T., Endo K., et al. "Influence of air contamination during heat-assisted plasma treatment on adhesion properties of polytetrafluoroethylene (PTFE)", RSC Advances, 9(40), 22900, 2019. https://doi.org/10.1039/c9ra01789e., Plasma surface treatment is typically not effective on fluoropolymers containing polytetrafluoroethylene (PTFE). It is reported that heat-assisted plasma (HAP) treatment at high temperatures (above 200 °C) under atmospheric pressure helium (He) plasma improves the adhesion properties of PTFE. In this study, we investigated the influence of the air concentration during HAP treatment on the adhesion properties of PTFE. Air concentration was controlled via ambient air inflow amount, in other words, base pressure. The PTFE samples HAP-treated in different air concentrations were thermally compressed with an unvulcanized isobutylene-isoprene rubber (IIR). Then, the PTFE/IIR adhesion strength was measured via T-peel test. We show that, when PTFE was HAP-treated in 0.01% air, its PTFE/IIR adhesion strength was over 2 N mm-1; the IIR underwent cohesion failure. However, the PTFE/IIR adhesion strength drastically decreased in the presence of air contamination. The relationships between air concentration during HAP treatment, adhesion properties of PTFE, surface chemical composition, surface morphology, and surface hardness were investigated and discussed.

Published
2019

50. Open-air-type Ar + H2O plasma treatment of polytetrafluoroethylene for improving Ag/PTFE adhesion strength: application to highly adhesive Ag direct wiring patterns.

Author

Ohkubo, Yuji, Kodama, Yoshinori, Nishino, Misa, Oshita, Takaya, Uehara, Tsuyoshi, Endo, Katsuyoshi, and Yamamura, Kazuya

Abstract

We performed an open-air-type plasma treatment of polytetrafluoroethylene (PTFE) at atmospheric pressure to increase the adhesion strength between PTFE and an Ag metal film obtained from Ag ink. When PTFE was Ar plasma-treated without H2O addition for 600 s, the coloration of the PTFE surface occurred, and the Ag/PTFE adhesion strength was 0.06 N mm−1. This adhesion strength was the same as that of the as-received PTFE (0.04 N mm−1). When the PTFE was Ar plasma-treated with the H2O addition of ca. 0.1% for 600 s, coloration did not occur, and the Ag/PTFE adhesion strength increased to 1.03 N mm−1. The effects of H2O addition to the Ar plasma on the Ag/PTFE adhesion strength, surface chemical composition, surface morphology, and the surface hardness were investigated and discussed in this study. [ABSTRACT FROM AUTHOR]

Published
2020
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