Tanaka, Takahisa

写真a

Affiliation

Faculty of Science and Technology, Department of Electronics and Electrical Engineering (Yagami)

Position

Associate Professor
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Career 【 Display / hide 】

  • 2013.04
    -
    2014.03

    Keio University, Faculty of Science and Technology, 助教

  • 2014.04
    -
    2015.03

    日本学術振興会, 特別研究員(DC2)

  • 2015.04
    -
    2016.03

    日本学術振興会, 特別研究員(PD)

  • 2016.04
    -
    2019.03

    Keio University, Faculty of Science and Technology, 助教

  • 2019.04
    -
    2023.03

    The University of Tokyo, The Graduate School of Engineering, Department of Materials Engineering, 助教

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Research Areas 【 Display / hide 】

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Electric and electronic materials

  • Nanotechnology/Materials / Inorganic materials and properties

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Research Keywords 【 Display / hide 】

  • 半導体デバイス

  • 半導体工学

  • 半導体物性

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Papers 【 Display / hide 】

  • Detection of PPB-Level H<inf>2</inf>S Concentrations in Exhaled Breath Using Au Nanosheet Sensors with Small Variability, High Selectivity, and Long-Term Stability

    Kato T., Tanaka T., Uchida K.

    ACS Sensors (ACS Sensors)  9 ( 2 ) 708 - 716 2024.02

    　View Summary

    The continuous monitoring of hydrogen sulfide (H2S) in exhaled breath enables the detection of health issues such as halitosis and gastrointestinal problems. However, H2S sensors with high selectivity and parts per billion-level detection capability, which are essential for breath analysis, and facile fabrication processes for their integration with other devices are lacking. In this study, we demonstrated Au nanosheet H2S sensors with high selectivity, ppb-level detection capability, and high uniformity by optimizing their fabrication processes: (1) insertion of titanium nitride (TiN) as an adhesion layer to prevent Au agglomeration on the oxide substrate and (2) N2 annealing to improve nanosheet crystallinity. The fabricated Au nanosheets successfully detected H2S at concentrations as low as 5.6 ppb, and the estimated limit of detection was 0.5 ppb, which is superior to that of the human nose (8-13 ppb). In addition, the sensors detected H2S in the exhaled breath of simulated patients at concentrations as low as 175 ppb while showing high selectivity against interfering molecules, such as H2, alcohols, and humidity. Since Au nanosheets with uniform sensor characteristics enable easy device integration, the proposed sensor will be useful for facile health checkups based on breath analysis upon its integration into mobile devices.

  • Understanding of a Pt thin-film H2 sensor under working conditions by AP-XPS and XAFS

    Ryo Toyoshima, Takahisa Tanaka, Taro Kato, Hitoshi Abe, Ken Uchida, Hiroshi Kondoh

    Chemistry Letters (Oxford University Press (OUP))  53 ( 2 )  2024.02

    ISSN  03667022

    　View Summary

    Abstract

    Operating principle of a Pt thin-film H2 gas sensor was investigated by a combination of surface sensitive ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) and bulk sensitive X-ray absorption fine structure (XAFS) techniques, which provided chemical and structure information under working conditions, coupled with electric resistivity measurements. It is evidenced that the sensor response was in a linear relation to both coverages of H and O atoms on the Pt surface. Moreover, the bulk structure of Pt remains unchanged under the H2­ exposure. These observations support that the resistivity change is associated with electron scattering in the near surface region.

  • A 65nm Cryogenic CMOS Design and Performance at 4.2K for Quantum State Controller Application

    Munehiro Tada, Koichiro Okamoto, Takahisa Tanaka, Makoto Miyamura, Hiroki Ishikuro, Ken Uchida, Toshitsugu Sakamoto

    IEEE Journal of the Electron Devices Society (Institute of Electrical and Electronics Engineers (IEEE))  12   28 - 33 2024

    　View Summary

    A performance evaluation of cryogenic CMOS circuit at liquid-helium temperature (4.2K) is conducted using a standard 65nm bulk CMOS for quantum state controller (QSC) applications. The ON-current (Ion) of the core n/pMOSFET are increased by 25% and 9% with excellent gate modulation (Ion/Ioff=~109). The cryogenic characteristics of copper interconnects in the back end of the line (BEOL), including line and via resistances, capacitances, and Joule-heating effect (JHE) are accurately assessed. The interconnect and via resistances decrease with temperature due to a reduction of electron-phonon scattering, resulting in resistances that are 75% and 20% lower at 4.2K compared to those at room temperature(RT). No significant change in inter-line capacitance and no severe JHE are observed in the Cu BEOL at 4.2K. The developed cell libraries for Simulation Program with Integrated Circuit Emphasis (SPICE) model and the technology file, which includes RC interconnect parameters, enable precise design of CMOS circuits at 4.2K. This results in a demonstrated +18.3% increase in speed or -16% reduction in power consumption for ring-oscillator (ROSC) at 4.2K, aligning well with the simulation results obtained from the developed model.

  • Hydrogen gas and the gut microbiota are potential biomarkers for the development of experimental colitis in mice

    Yuta Fujiki, Takahisa Tanaka, Kyosuke Yakabe, Natsumi Seki, Masahiro Akiyama, Ken Uchida, Yun-Gi Kim

    Gut Microbiome (Cambridge University Press (CUP))     1 - 24 2023.11

    Lead author, Accepted

  • Alkyl-Chain-Length and Temperature Dependencies of Sensor Responses to Aliphatic Alcohols in Nanostructured Pt-Based Sensors

    Yusuke Hamanaka, Takahisa Tanaka, Ken Uchida

    ACS Applied Nano Materials (American Chemical Society (ACS))  6 ( 18 ) 16433 - 16441 2023.09

    Accepted,  ISSN  2574-0970

    　View Summary

    Long-alkyl-chain alcohols are promising biofuel alternatives to fossil fuels; however, their detection has been a challenging task. In this study, the responses of nanoscale Pt-based sensors to aliphatic alcohols were examined, focusing on alkyl-chain-length and temperature dependencies. Atomistic simulations with a universal neural network potential were used to analyze the reaction and activation energies. Two types of Pt-based sensors were fabricated: a Pt nanosheet resistor sensor (PtNS) and a Pt nanoparticle-decorated graphene field-effect transistor sensor (PtNP-GFET). PtNP-GFET exhibited considerably higher sensor responses to 1-heptanol than to ethanol at 225 °C; moreover, PtNS showed the opposite alkyl-chain-length dependence compared to the response of PtNP-GFET at the same temperature. At a lower temperature of 150 °C, the sensor response toward ethanol and 1-heptanol in the case of PtNP-GFET was nearly identical, indicating that the response was primarily influenced by the concentration of hydroxyl groups. Atomistic simulation analysis revealed that the dehydrogenation reaction of the hydrocarbons near the hydroxyl groups was thermodynamically more favorable on the Pt147 nanocluster than on the Pt(111) surface. The dehydrogenation from the alkyl chain by PtNP was confirmed in alkanes; this dehydrogenation caused a higher sensor response of PtNP-GFET to 1-heptanol than to ethanol at 225 °C. Overall, employing nanomaterials, namely nanostructured Pt catalysts and a graphene-FET transducer, and using multiple sensing temperatures are key factors for realizing long-alkyl-chain alcohol recognitions. A low temperature of 150 °C is suitable for hydroxyl group sensing, while a high temperature of 225 °C is preferable for hydrocarbon group sensing.

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Presentations 【 Display / hide 】

  • Experimental Investigation of Interface Defect Properties in PtOx/ZnO Schottky Diodes by Deep Level Transient Spectroscopy

    M. Matsumura, T. Tanaka, K. Uchida

    34th International Microprocesses and Nanotechnology Conference (MNC), 

    2021.10

  • Enhanced electron phonon scattering in Si nanowires covered by oxide

    T. Tanaka, K. Uchida

    240th ECS Meeting, 

    2021.10

  • Selective Recognition of Acetone in Air Against Hydrogen By Impedance Measurement of Two-Terminal Electrochemical Sensors Based on Ionic Liquids

    Y. Hamanaka, T. Tanaka, K. Uchida

    240th ECS Meeting, 

    2021.10

  • A Wide Range and High Accuracy Sensor Interface with Switching Regulator for Coin-Cell Powered Tiny Wirelesss Sensor Node

    K. Tatehora, Y. Shiiki, S. Nakagawa, T. Tanaka, K. Uchida, H. Ishikuro

    IEEE International Symposium on Circuits and Systems (ISCAS), 

    2020.10

  • Experimental Evidence for Temperature Dependence of Adsorbate-induced Scattering in Metal Nanosheets and Its Implication to Gas Sensing Applications

    Taro Kato, Takahisa Tanaka, Takeaki Yajima, Ken Uchida

    2020 International Conference on Solid State Devices and Materials, 

    2020.09

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

  • イオン液体のインピーダンスによる高選択的マルチガスセンシング

    2024.04
    -
    2027.03

    基盤研究(C), Principal investigator

  • 半導体表面/界面における特異な電子フォノン散乱の起源の解明

    2019.04
    -
    2023.03

    日本学術振興会, 科学研究費助成事業, 若手研究, No Setting

    　View Summary

    本年度は主に、1)シリコンナノ構造界面におけるフォノン散乱の変調と2)金属系材料の抵抗率計算で進展があった。
    1)シリコンナノ構造界面におけるフォノン散乱の変調については、昨年度まで実施していた分子動力学計算・強結合近似計算・量子輸送計算を連携した手法を用いて移動度の温度依存性を計算した。その結果、酸化膜で被覆されたシリコンナノワイヤ中の電子移動度の方が、水素終端シリコンナノワイヤ中の電子移動度よりも強い温度依存性を持つことを明らかにした。これは、昨年度までで判明した酸化膜被覆シリコンナノワイヤにおける電子移動度の劣化が、界面ラフネス由来ではなくフォノン散乱の変調であることを示唆している。一方で、ゲルマニウムナノワイヤに対して同様の計算を実施した場合は、酸化膜の有無は顕著な移動度変化を発生させなかった。これはシリコンとゲルマニウムの機械的特性の違いに起因していると予想されるため、今後検証を行う。
    2)金属系材料の抵抗率計算では、本研究で開発した手法が別種の材料系でも適用可能かを検討した。白金ナノシートでは、表面に吸着した水素と酸素の量に依存して電気抵抗が変化するため、水素ガスセンサとして用いられる。しかし、フォノン散乱と吸着ガスによる散乱が共存する系を定量的に解析することは困難であった。本研究では、反応力場に基づく分子動力学計算・密度半関数計算・量子輸送計算を連携することで、半導体ナノ構造と同様にキャリア散乱を取り扱うことに成功した。

  • 次世代トランジスタに向けた酸化膜近傍におけるキャリア散乱モデルの確立

    2014.04
    -
    2016.03

    日本学術振興会, 科学研究費助成事業, 特別研究員奨励費, No Setting

    　View Summary

    本研究は，酸化膜近傍におけるキャリア散乱機構のモデリングを行うことを目的としている．最終年度となる本年度は，酸化膜近傍におけるフォノン散乱の変形ポテンシャルのモデリングと，クーロン散乱に影響する酸化膜近傍でのイオン化エネルギーの上昇のモデリングを行った．
    まず，フォノン散乱の変形ポテンシャルのモデリングでは，薄膜Silicon-On-Insulator(SOI)トランジスタ中の移動度の温度依存性を測定した．実験的な移動度の温度依存性に対して計算値を比較することにより，酸化膜近傍の変形ポテンシャル上昇を考慮することが，正確な移動度の温度依存性の再現に必要であることを明らかにした．さらに，変形ポテンシャル上昇を考慮したモデルで，薄膜SOIトランジスタに加えてバルクSiトランジスタとジャンクションレス厚膜SOIトランジスタの移動度も統一的に説明できることを明らかにした．
    また，クーロン散乱に影響する酸化膜近傍のイオン化エネルギー上昇のモデリングでは，薄膜SOIトランジスタ中のイオン化エネルギーをキャリア濃度の温度依存性から実験的に求めた．得られたイオン化エネルギーを計算値と比較することで，任意の不純物濃度における，酸化膜近傍でのイオン化エネルギーを記述するモデルの構築に成功した．このモデルにより，高不純物濃度における酸化膜近傍のイオン化率を評価できるようになったため，クーロン散乱に寄与するイオン化不純物の量をより正確に見積もれると期待される．

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Courses Taught 【 Display / hide 】

  • SOLID STATE ENGINEERING

    2024

  • RECITATION IN ELECTRONICS AND INFORMATION ENGINEERING

    2024

  • PHYSICS D

    2024

  • PHYSICS C

    2024

  • NANODEVICE ENGINEERING

    2024

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Committee Experiences 【 Display / hide 】

  • 2019
    -
    Present

    Program Committee Members, International Microprocesses and Nanotechnology Conference

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