Development of structural optimization method for thermoelectric conversion and novel heat transfer materials

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K14664
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 19020:Thermal engineering-related
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: Hori Takuma 東京農工大学, 工学(系)研究科(研究院), 准教授 (50791513)
• Project Period (FY): 2020-04-01 – 2022-03-31
• Keywords: 熱伝導率 / シリコン薄膜 / 熱電変換 / フォノン輸送

Outline of Final Research Achievements

An optimization method for thermal conductivity of nanostructured silicon thin films is developed. The optimization is realized by combining the phonon ray tracing and simulated annealing method. More specifically, the nanostructured thin films consisted of square lattices is gradually varied in each step. Phonon mean free path of each structure, which is the dominant factor for thermal conductivity, is evaluated by the ray tracing simulations. The new structure is accepted when its mean free path is closer to the optimum; if not, it is also accepted according to probability to avoid local optimum solution. The validity of the developed method is confirmed by comparing the results with those obtained by a brutal search. The influence of the parameters of the simulated annealing method on the predicted optimal structure is also verified, indicating that the parameter tuning leads to more efficient optimization.

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

シリコンは資源としての豊富さや無毒性などの長所を持つことから，様々なデバイスに利用されている．一方で，熱電変換材料としてはその高い熱伝導率に起因した低い変換効率が課題となっている．そうした中で，本研究では熱伝導率を下げる最適ナノ構造の探索方法を開発したため，デバイスの進歩に直接的に貢献することを期待する．同時に，熱電変換材料だけにとどまらず，開発した手法は様々な場面に際して応用可能であると考える．また，「ナノ構造中の熱輸送にとって決定的に重要な要素は何か」といった学術の基礎的理解を追求する研究を応用の観点から刺激する作用も期待できる．