Effect of three-dimensional Si phononic crystal on thermal-electric characteristics

• Project/Area Number: 17K05032
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Applied materials
• Research Institution: Nara Institute of Science and Technology
• Principal Investigator: Ishikawa Yasuaki 奈良先端科学技術大学院大学, 先端科学技術研究科, 准教授 (70581130)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2019: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2017: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: 3次元周期的ナノ構造 / 液体材料 / テンプレート / 液体シリコン / 半導体物性 / 熱工学 / 材料加工・処理

Outline of Final Research Achievements

It is crucial that thermal conductivity is suppressed by the nano-structure embedded in semiconductor materials when we improve the efficiency of a thermoelectric generator. This research introduced a fabrication technology of nano-structure in semiconductor thin-films in a simple way and investigated an effect of the nano-structure in terms of thermal conductivity.
The laser-based technique successfully provided 3-dimensional periodic nano-structures in ZnO and Si. The results of the thermal conductivity measurement for the fabricated nano-structured ZnO yielded the thermal conductivity as low as one two-hundredth of that of the conventional ZnO thin film, indicating that the introduced technology can improve the efficiency of a thermoelectric generator.

Academic Significance and Societal Importance of the Research Achievements

身の回りには利用できていない熱が多量に存在し、かつそれらは廃棄されている。これら廃熱を高効率に再利用する熱電素子を環境にやさしい材料で実現することが求められている。またナノ構造形成には、複雑なプロセスが必要であった。本研究では、環境にやさしいＺｎＯやＳｉ材料を用い、かつ簡単なプロセスで熱電特性の改善が可能なナノ構造形成に成功した。形成したナノ構造は周期的特性を有している。この構造特性が熱電特性の改善に有効であることは理論的には示されていたが、実験的にも本研究で明らかになり、理論的考察の確からしさを支持する結果となった。

Research Products

• [Int'l Joint Research] KAIST(韓国)
• [Int'l Joint Research] KAIST(韓国)
• [Journal Article] Removing Process of the Three-Dimension Periodic Nanostructure Fabricated from KMPR Photoresist (2019)
  • Author(s): Xudongfang Wang, Yasuaki Ishikawa, Shinji Araki, Mutsunori Uenuma, and Yukiharu Uraoka
  • Journal Title: Jpn. J. Appl. Phys. Volume: 58 Issue: SD Pages: SDDF08-SDDF08
  • DOI: 10.7567/1347-4065/ab0dea
  • Peer Reviewed
• [Journal Article] Fabrication of Nanoshell-Based 3D Periodic Structures by Templating Process using Solution-derived ZnO (2017)
  • Author(s): Araki Shinji、Ishikawa Yasuaki、Wang Xudongfang、Uenuma Mutsunori、Cho Donghwi、Jeon Seokwoo、Uraoka Yukiharu
  • Journal Title: Nanoscale Research Letters Volume: 12 Issue: 1 Pages: 419-419
  • DOI: 10.1186/s11671-017-2186-6
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] ZnO溶液を用いたテンプレートプロセスによる三次元周期的ナノ構造の作製 (2020)
  • Author(s): 王 旭東方, 石河 泰明, 上沼 睦典, 浦岡 行治
  • Organizer: 第67回応用物理学会春季学術講演会
• [Presentation] Effects of phase shift mask design on three-dimension nanostructure fabrication (2020)
  • Author(s): Pongsakorn Sihapitak, Yasuaki Ishikawa, Xudongfang Wang, Mutsunori Uenuma, Yukiharu Uraoka
  • Organizer: 第67回応用物理学会春季学術講演会
• [Presentation] Removing Process of the Three-Dimension Periodic Nanostructure Fabricated from KMPR Photoresist (2018)
  • Author(s): Xudongfang Wang, Yasuaki Ishikawa, Mutsunori Uenuma and Yukiharu Uraoka
  • Organizer: 31st International Microprocesses and Nanotechnology Conference
  • Int'l Joint Research
• [Presentation] Three-dimension periodic nano-structure fabricated by proximity nano-patterning process (2017)
  • Author(s): Xudongfang Wang, Yasuaki Ishikawa, Shinji Araki, Yukiraru Uraoka, and Seokwoo Jeon
  • Organizer: 電子情報通信学会 電子ディスプレイ研究会