USAMI Yuki

写真a

Title

Assistant Professor

Laboratory

2-4 Hibikino, Wakamatsu-ku, Kitakyushu-shi, Fukuoka

Scopus Paper Info  
Total Paper Count: 0  Total Citation Count: 0  h-index: 2

Citation count denotes the number of citations in papers published for a particular year.

Undergraduate Education 【 display / non-display

  • 2015.03   Osaka University   Faculty of Science   Graduated   JAPAN

Post Graduate Education 【 display / non-display

  • 2020.03  Osaka University  Graduate School, Division of Natural Science  Doctoral Program  Completed  JAPAN

Degree 【 display / non-display

  • Osaka University -  Master  2020.03

Biography in Kyutech 【 display / non-display

  • 2020.04
    -
    Now

    Kyushu Institute of TechnologyGraduate School of Life Science and Systems Engineering   Department of Human Intelligence Systems   Assistant Professor  

Biography before Kyutech 【 display / non-display

  • 2019.04
    -
    2020.03

      Special researcher of the Japan Society for the Promotion of Science   JAPAN

Specialized Field (scientific research fund) 【 display / non-display

  • Applied materials

 

Publications (Article) 【 display / non-display

  • Conductance enhancement of PCBM thin films by gas-phase Au-doping

    Nakajima Tsuyoshi, Misaka Tomoki, Usami Yuki, Otsuka Yoichi, Ohyama Hiroshi, Matsumoto Takuya

    Abstract book of Annual Meeting of the Japan Society of Vacuum and Surface Science  ( The Japan Society of Vacuum and Surface Science )  2020 ( 0 )   2020.12

     View Summary

    <p>We found that conductance of PCBM thin films is enhanced by thermal vapor deposition of a small amount of gold, in which amount multiple tunneling conduction through gold islands can't occur, so in PCBM with gold deposition there is electrical conduction with other mechanism. The origin of such significant conductance enhancement is not revealed, but there is one possibility that gold works as the dopant of PCBM films. In this presentation, we will discuss it with spectroscopic data.</p>

    DOI CiNii

  • Toward physical reservoir system composed of polyaniline-Au nanoparticle random network

    Kawashima Yuya, Usami Yuki, Kotooka Takumi, Tanaka Hirofumi, Matsumoto Takuya

    Abstract book of Annual Meeting of the Japan Society of Vacuum and Surface Science  ( The Japan Society of Vacuum and Surface Science )  2020 ( 0 )   2020.12

     View Summary

    <p>Reservoir computing (RC) is an information processing system that can replace the operations performed in the reservoir layer with physical behavior. We have previously shown that nonlinear <i>I-V</i> characteristics occur in a network consisting of self-doped polyaniline molecules (SPAN) and Au nanoparticles (AuNP). In this study, the nonlinear electrical and storage properties between multiple-input and multiple-output electrodes were investigated by nano-gap electrodes to explore the applicability of the SPAN-AuNP network to RC.</p>

    DOI CiNii

  • Frequency dependence dielectrophoresis technique for bridging graphene nanoribbons

    Aji W.W., Usami Y., Hadiyawarman , Oyabu R., Tanaka H.

    Applied Physics Express    13 ( 10 )   2020.10  [Refereed]

     View Summary

    © 2020 The Japan Society of Applied Physics We succeeded in bridging unzipped graphene nanoribbons (GNRs) and separating them from unwanted single-walled carbon nanotubes (SWNTs) using a frequency-dependent dielectrophoresis (DEP) method by varying the frequency and applied voltage used for future assembly. Atomic force micrographs and Raman spectra proved that unzipped GNRs were successfully bridged by the DEP method at frequencies higher than 13 MHz. The theoretical calculation also supported the finding that only GNRs were collected from a mixture of SWNTs/GNRs suspensions.

    DOI Scopus

  • Local-field-induced current noise in shape-limited self-doped polyaniline

    Bao J., Otsuka Y., Etoh R., Usami Y., Matsumoto T.

    Nanotechnology    31 ( 36 )   2020.09  [Refereed]

     View Summary

    © 2020 IOP Publishing Ltd. Electronic noise generators are an essential component of molecular neuromorphic devices. To realize molecular noise generators with a high degree of freedom for design and integration into molecular devices, the utilization of the local electric field for the modulation of electrical conduction via a shape-limited conductive polymer is one promising strategy. Herein, a molecular noise generator composed of thin self-doped polyaniline (SPAN) lines is reported. SPAN lines fabricated via fountain pen lithography on SiO2/Si substrates were found to generate current noise upon laser irradiation. This current noise exhibited white-noise-like power spectral density in the frequency range of 1-25 Hz and was independent of temperature. Multiple independent noise generation on the same substrate was also successfully demonstrated. The present results indicate that the noise generation mechanism involves the local modulation of hopping conduction via SPAN lines owing to the spatial proximity of the conduction path in the SPAN line to the surface photovoltage region of the SiO2/Si interface. This on-site random noise generation in shape-limited conductive polymers is expected to be beneficial for the realization of molecular neuromorphic devices.

    DOI Scopus

  • Visualization of Charge Migration in Conductive Polymers via Time-Resolved Electrostatic Force Microscopy

    Kajimoto K., Araki K., Usami Y., Ohoyama H., Matsumoto T.

    Journal of Physical Chemistry A    124 ( 25 ) 5063 - 5070   2020.06  [Refereed]

     View Summary

    © 2020 American Chemical Society. Charge dynamics play an important role in numerous natural phenomena and artificial devices, and tracking charge migration and recombination is crucial for understanding the mechanism and function of systems involving charge transfer. Tip-synchronized pump-probe electrostatic force microscopy simultaneously permits highly sensitive detection, microsecond time resolution, and nanoscale spatial resolution, where the spatial distribution in static measurement (usual EFM) reflects differences in the carrier density and the time evolution reveals the surface carrier mobility. By using this method, carrier injection and ejection in sulfonated polyaniline (SPAN) thin films were visualized. Comparison of tr-EFM results of SPAN thin films with different doping levels revealed the individual differences in carrier density and mobility.

    DOI Scopus

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