| Project/Area Number |
23K26489
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| Project/Area Number (Other) |
23H01796 (2023)
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Multi-year Fund (2024)
Single-year Grants (2023) |
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| Section | 一般 |
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| Review Section |
Basic Section 28020:Nanostructural physics-related
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| Research Institution | National Institute for Materials Science |
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Principal Investigator |
湯 代明 国立研究開発法人物質・材料研究機構, ナノアーキテクトニクス材料研究センター, 主幹研究員 (50646271)
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| Co-Investigator(Kenkyū-buntansha) |
石原 伸輔 国立研究開発法人物質・材料研究機構, ナノアーキテクトニクス材料研究センター, 主幹研究員 (30644067)
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| Project Period (FY) |
2023-04-01 – 2027-03-31
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| Project Status |
Granted (Fiscal Year 2024)
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| Budget Amount *help |
¥18,980,000 (Direct Cost: ¥14,600,000、Indirect Cost: ¥4,380,000)
Fiscal Year 2026: ¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2025: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Fiscal Year 2024: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2023: ¥10,920,000 (Direct Cost: ¥8,400,000、Indirect Cost: ¥2,520,000)
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| Keywords | Carbon nanotubes / Molecular junction / Electron microscopy / Chirality transformation / Gas sensor / Carbon nanotube / Machine learning / carbon nanotube / chirality / molecular junction / transport properties / quantum sensors |
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| Outline of Research at the Start |
We aim to develop gas sensors for individual molecules, based on CNT molecular junction transistors, by elucidating the chirality transformation mechanism, investigating the transport properties, and studying the electrochemical properties interacting with molecular adsorbents.
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| Outline of Annual Research Achievements |
Carbon nanotubes (CNTs) are promising for gas sensors at molecular level, because of the extraordinary electrical properties associated with the unique one-dimensional geometry. Depending on the helical structure, so called “chirality”, CNTs are either metallic or semiconducting. Such chirality-dependence has been recognized as an inherent and permanent property, until recently, we realized chirality transformation of a metallic CNT, resulting in an ultrashort semiconducting nanotube channel within a metallic nanotube to form a molecular junction.
In this fiscal year, we have made progresses in (1) controlled growth of CNTs assisted by machine learning; (2) development of advanced 4D-STEM method and revealed the stability map and transformation routes during the manipulation of the chirality structures.
In the next steps, the chirality transformation mechanisms will be quantitatively investigated by using MEMS chips. Machine learning will be adopted for predictive fabrication of CNT molecular junctions. And ultimately, CNT junction based sensors will be developed for the detection of individual molecules in real-time. This research will not only provide fundamental insights into molecular dynamics and electronics, but also pave the way to the development of quantum sensors with real-time responses to individual molecules.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
The purposes of the project include (1) elucidate the CNT chirality transformation mechanism at atomic level, (2) to precisely control the local CNT chirality, and (3) to understand the transport properties of the CNT junction transistors. The plan for FY2023 is mainly to investigate the chirality transformation mechanism. We have made progresses in (1) machine learning-assisted growth of single walled CNTs, (2) quantitative investigation of the chirality transformation process by advanced in situ and 4D-STEM.
CNTs with controlled structures are the basis for fabricating CNT molecule junction devices. We developed a high-throughput strategy to investigate the statistical patterns in catalyst activity and selective growth of SWCNTs. Statistical patterns of the yield, quality and selectivity are associated with the alloy composition, revealing a negative correlation between the yield and enrichment of s-SWCNTs. Semiconducting SWCNTs with a purity higher than 90% were obtained (Carbon 2023, 118073).
Our original concept of “chirality engineering” has been widely accepted by the community. In an invited review, we summarized approaches to control global and local CNT chiralities by growth, separation, and transformation. We discussed opportunities and challenges for chirality engineering towards surpassing the performance of conventional electronic devices, and development of unconventional CNT quantum electronics (Nature Reviews Electrical Engineering 2024, 1 (3), 149-162).
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| Strategy for Future Research Activity |
To fulfill the goals of the project to understand the CNT chirality transformation mechanism, and to establish the dependence of transport properties on the atomic structure, and finally to develop quantum sensors based on the electrochemical interactions of CNT junctions and gas molecules, future plan includes (1) quantitative investigation of chirality transformation mechanism by MEMS devices and simulation at multiple length scales, (2) predictable chirality transformation and fabrication of CNT junction devices by applying machine learning, (3) fabrication of CNT junction devices on chips to study the transport properties and electrochemical properties with the presence of gas molecules.
Specifically, the deformation of individual CNTs under mechanical stress, temperature and electron irradiation will be realized by developing MEMS chips and the process will be monitored by in situ TEM observations. The atomic structure and chirality of CNTs will be characterized by Cs-corrected TEM imaging and electron diffraction. The temperature of the Joule heated CNTs will be measured by STEM-EELS using the shift of plasmon peaks. For machine learning modelling, input parameters will include the structure of the original and the resulting nanotube, the electrical properties of the original nanotube, and processing parameters. The resulted nanotube chirality will be the label of the target. After training, the model will be used to predict the processing parameters for the desired chirality transformations.
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