Hybrid fabrication technology for nano-plasmonic devices

• Project/Area Number: 19K15423
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 28050:Nano/micro-systems-related
• Research Institution: Tokyo Institute of Technology (2023); Tokyo University of Science (2019-2022)
• Principal Investigator: 大久保 喬平 東京工業大学, 物質理工学院, 助教 (20822951)
• Project Period (FY): 2019-04-01 – 2025-03-31
• Project Status: Granted (Fiscal Year 2023)
• Budget Amount: ¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000); Fiscal Year 2021: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2020: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2019: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
• Keywords: プラズモニクス / ナノフォトニクス / ナノ・マイクロ微細加工 / 共振器 / 近赤外光 / ナノ加工技術 / 金属ナノ粒子 / ナノ・マイクロ加工

Outline of Research at the Start

トップダウン・ボトムアップ手法を組み合わせたハイブリッドナノ構造作製技術により、パターニングおよび金属層エッチング不要なナノプラズモニクス応用に向けた金属ナノ構造のアレイ表面を実現する。ナノ構造作製技術は高精度なマイクロマシニング手法による鋳型表面と鋳型を用いた金属成膜・結晶化ナノ構造を形成する技術からなる。

Outline of Annual Research Achievements

ナノプラズモニック・デバイス構築において、ナノ構造作製技術とプロセス設計は高性能・高精度なデバイス形成の鍵となる。金属ナノ粒子の化学合成に代表されるボトムアッププロセスや金属薄膜への微細加工などのトップダウンプロセスとそれらの組み合わせが多数報告されているが、大面積における20 nm以下の金属ナノギャップ作成は実現例に乏しい。本研究では、10 nm以下の間隙を持つ均一な金属ナノ粒子集合体を大面積で形成する作製技術の確立を目指す。特に、局在型プラズモン共鳴の基本ユニットとなる金属ナノ粒子とその間隔を制御した七量体構造は近赤外域の急峻な暗モードを持つ共振器になることから、金属ナノ粒子七量体の設計・作製に取り組んでいる。40 nm厚 SiN/Si基板上にの長方形（長辺 200 nm, 短辺 150 nm）を正六角形の中心および頂点配置した7量体テンプレートを前年度作製し、再現性のあるプロトコルを確立した。SiNテンプレート間隙にV字型溝を形成するために、水酸化カリウム溶液を用いたウェットプロセス条件の確立した。2023年度より所属変更に伴い実験装置・プロセス条件を見直す必要が出たため、超高速電子線描画装置（Advantest F-7000S）から直描型電子線描画装置（Elionix）に変更し、露光・現像条件の再検討を行った。また、反応性イオンエッチング装置によるSiN薄膜のエッチングに関しても装置の変更に伴いエッチングレートの計測などの検討を行った。

Current Status of Research Progress

4: Progress in research has been delayed.

Reason

電子線描画装置の描画条件検討およびエッチング装置の条件検討は順調に進んでいる。金属薄膜形成装置による10nm程度のAu薄膜をSiN/Si基板上に形成し、初期的ではあるが電気炉によるアニーリング処理による金属ナノ粒子の形成を確認した。

Strategy for Future Research Activity

当初計画した通りの光学測定系の構築は現時点では不十分であるが、学内共通機器としてラマン分光顕微鏡が利用可能であり、作製した共振器デバイスの特性評価に向けて検討を進めている状態である。ナノデバイス作製とその評価に必要な環境・データが揃いつつある。

Research Products

• [Journal Article] Designing Er³⁺/Ho³⁺-Doped Near-Infrared (NIR-II) Fluorescent Ceramic Particles for Avoiding Optical Absorption by Water (2022)
  • Author(s): Umezawa M, Kurahashi H, Nigoghosian K, Okubo K, Soga K
  • Journal Title: Journal of Photopolymer Science and Technology Volume: 35 Issue: 1 Pages: 9-16
  • DOI: 10.2494/photopolymer.35.9
  • ISSN: 0914-9244, 1349-6336
  • Year and Date: 2022-12-16
  • Peer Reviewed / Open Access
• [Journal Article] The effect of Gd-DOTA locations within PLGA-b-PEG micelles encapsulated IR-1061 on bimodal over-1000 nm near-infrared fluorescence and magnetic resonance imaging (2022)
  • Author(s): 7.T.K.D. Doan, M. Umezawa, K. Okubo, M. Kamimura, M. Yamaguchi, H. Fujii, K. Soga
  • Journal Title: Biomaterials Science Volume: 10 Issue: 21 Pages: 6244-6257
  • DOI: 10.1039/d2bm01213h
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Three dimensional lifetime-multiplex tomography based on time-gated capturing of near-infrared fluorescence images (2022)
  • Author(s): Umezawa M, Miyata K, Okubo K, Soga K
  • Journal Title: Applied Sciences Volume: 12 Issue: 15 Pages: 7721-7721
  • DOI: 10.3390/app12157721
  • Peer Reviewed / Open Access
• [Journal Article] The influence of Gd-DOTA conjugating ratios to PLGA-PEG micelles encapsulated IR-1061 on bimodal over-1000 nm near-infrared fluorescence and magnetic resonance imaging (2022)
  • Author(s): Doan Thi Kim Dung、Umezawa Masakazu、Ohnuki Kazunobu、Nigoghossian Karina、Okubo Kyohei、Kamimura Masao、Yamaguchi Masayuki、Fujii Hirofumi、Soga Kohei
  • Journal Title: Biomaterials Science Volume: 10 Issue: 5 Pages: 1217-1230
  • DOI: 10.1039/d1bm01574e
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Heat treatment effects for controlling dye molecular states in hydrophobic core of over-1000 nm near-infrared fluorescent micellar nanoparticles (2022)
  • Author(s): M. Umezawa, H. Kobayashi, K. Ichihashi, S. Sekiyama, K. Okubo, M. Kamimura, K. Soga
  • Journal Title: ACS Omega Volume: 7 Issue: 7 Pages: 5817-5824
  • DOI: 10.1021/acsomega.1c05771
  • Peer Reviewed / Open Access
• [Journal Article] Gastric cancer detection by two-step learning in near infrared hyperspectral imaging (2022)
  • Author(s): A. Yahata, H. Takemura, R. Iwanami, M. Umezawa, K. Okubo, K. Soga, T. Takamatsu, T. Mitsui, T. Kadota, T. Kuwata, H. Ikematsu, H. Yokota
  • Journal Title: Journal of Information and Communication Engineering Volume: 7 Pages: 467-473
  • Peer Reviewed
• [Journal Article] Effect of enantiomeric structure of hydrophobic polymer on encapsulation property of near infrared fluorescent dye for in vivo deep imaging (2022)
  • Author(s): K. Ichihashi, M. Umezawa, Y. Ueya, K. Okubo, E. Takamoto, T. Matsuda, M. Kamimura, K. Soga
  • Journal Title: RSC Advances Volume: 12 Issue: 3 Pages: 1310-1318
  • DOI: 10.1039/d1ra08330a
  • Peer Reviewed / Open Access
• [Journal Article] Influence of the difference in refractive index on the interface of an object and the surroundings in near-infrared fluorescence tomography (2022)
  • Author(s): Takematsu Maho、Umezawa Masakazu、Sera Toshihiro、Kitagawa Yuichi、Kurahashi Hiroyuki、Yamada Shuta、Okubo Kyohei、Kamimura Masao、Yokota Hideo、Soga Kohei
  • Journal Title: Applied Optics Volume: 61 Issue: 2 Pages: 638-638
  • DOI: 10.1364/ao.445357
  • Peer Reviewed / Open Access
• [Journal Article] Review - Concept and Application of Thermal Phenomena at 4f Electrons of Trivalent Lanthanide Ions in Organic/Inorganic Hybrid Nanostructure (2021)
  • Author(s): Okubo Kyohei、Umezawa Masakazu、Soga Kohei
  • Journal Title: ECS Journal of Solid State Science and Technology Volume: 10 Issue: 9 Pages: 096006-096006
  • DOI: 10.1149/2162-8777/ac2327
  • Peer Reviewed / Open Access
• [Journal Article] Effect of polarization of surrounding organic molecules on upconversion emission of β-NaYF4 Co-Doped with Er3+ and Yb3+ (2021)
  • Author(s): Nomura Koki、Umezawa Masakazu、Tezuka Keiko、Tasaki Tomomi、Okubo Kyohei、Soga Kohei
  • Journal Title: Journal of Luminescence Volume: 239 Pages: 118394-118394
  • DOI: 10.1016/j.jlumin.2021.118394
  • Peer Reviewed
• [Journal Article] Upconversion Luminescent Nanostructure with Ultrasmall Ceramic Nanoparticles Coupled with Rose Bengal for NIR-Induced Photodynamic Therapy (2021)
  • Author(s): Tezuka Keiko、Umezawa Masakazu、Liu Te-I、Nomura Koki、Okubo Kyohei、Chiu Hsin-Cheng、Kamimura Masao、Soga Kohei
  • Journal Title: ACS Applied Bio Materials Volume: 4 Issue: 5 Pages: 4462-4469
  • DOI: 10.1021/acsabm.1c00213
  • Peer Reviewed / Open Access
• [Journal Article] Near Infrared Fluorescent Nanostructure Design for Organic/Inorganic Hybrid System (2021)
  • Author(s): Okubo Kyohei、Umezawa Masakazu、Soga Kohei
  • Journal Title: Biomedicines Volume: 9 Issue: 11 Pages: 1583-1583
  • DOI: 10.3390/biomedicines9111583
  • Peer Reviewed / Open Access
• [Journal Article] Over 1000 nm Near-Infrared Multispectral Imaging System for Laparoscopic In Vivo Imaging (2021)
  • Author(s): Takamatsu Toshihiro、Kitagawa Yuichi、Akimoto Kohei、Iwanami Ren、Endo Yuto、Takashima Kenji、Okubo Kyohei、Umezawa Masakazu、Kuwata Takeshi、Sato Daiki、Kadota Tomohiro、Mitsui Tomohiro、Ikematsu Hiroaki、Yokota Hideo、Soga Kohei、Takemura Hiroshi
  • Journal Title: Sensors Volume: 21 Issue: 8 Pages: 2649-2649
  • DOI: 10.3390/s21082649
  • Peer Reviewed / Open Access
• [Journal Article] Visualization of quantitative lipid distribution in mouse liver through near-infrared hyperspectral imaging (2021)
  • Author(s): Okubo Kyohei、Kitagawa Yuichi、Hosokawa Naoki、Umezawa Masakazu、Kamimura Masao、Kamiya Tomonori、Ohtani Naoko、Soga Kohei
  • Journal Title: Biomedical Optics Express Volume: 12 Issue: 2 Pages: 823-823
  • DOI: 10.1364/boe.413712
  • Peer Reviewed / Open Access
• [Journal Article] Size-controlled bimodal in vivo nanoprobes as near-infrared phosphors and positive contrast agents for magnetic resonance imaging (2021)
  • Author(s): Okubo Kyohei、Takeda Ryuta、Murayama Shuhei、Umezawa Masakazu、Kamimura Masao、Osada Kensuke、Aoki Ichio、Soga Kohei
  • Journal Title: Science and Technology of Advanced Materials Volume: 22 Issue: 1 Pages: 160-172
  • DOI: 10.1080/14686996.2021.1887712
  • Peer Reviewed / Open Access
• [Journal Article] NIR Hyperspectral Imaging (2020)
  • Author(s): Okubo Kyohei
  • Journal Title: Transparency in Biology Volume: 1 Pages: 203-222
  • DOI: 10.1007/978-981-15-9627-8_10
  • ISBN: 9789811596261, 9789811596278
• [Presentation] Hyperspectral imaging and detection mapping of in vivo biological tissues applying near-infrared laparoscope (2022)
  • Author(s): R. Fukushima, T. Takamatsu, A. Mori, K. Sato, K. Okubo, M. Umezawa, N. Takeshita, H. Hasegawa, H. Yokota, K. Soga, H. Takemura
  • Organizer: SPIE Photonics West
  • Int'l Joint Research
• [Presentation] Near infrared hyperspectral imaging for biomedical applications including lipid visualization in liver and submucosal tumor detection (2022)
  • Author(s): K. Okubo, M. Umezawa, K. Soga
  • Organizer: Spectral shapIng for biomedical and energy applicaTions (SHIFT 2022)
  • Int'l Joint Research
• [Presentation] Strategy for designing near infrared fluorescent nanostructure with organic and inorganic hybrid system (2022)
  • Author(s): K. Okubo, M. Umezawa, K. Soga
  • Organizer: 5th International Conference on Chromogenic and Emissive Materials 2022 (I3CEM2022)
  • Int'l Joint Research
• [Book] Transparency in Biology (2021)
  • Author(s): Kohei Soga, Masakazu Umezawa, and Kyohei Okubo (Eds.)
  • Total Pages: 263
  • Publisher: Springer Singapore
  • ISBN: 9789811596261