Drastic reduction in thermal conductivity of binary or ternary group-IV alloy by introduction of multiple phonon scattering centers

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K13786
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 21050:Electric and electronic materials-related
• Research Institution: Shizuoka University
• Principal Investigator: Shimura Yosuke 静岡大学, 電子工学研究所, 助教 (40768941)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Keywords: ゲルマニウム / スズ / 熱電変換 / 結晶成長 / 多結晶 / 薄膜 / X線非弾性散乱

Outline of Final Research Achievements

In order to improve the efficiency of thermoelectric device, impact of introduction of Sn atoms into a polycrystalline SiGe alloy on thermal conductivity was investigated. The crystallization of the SiGeSn polycrystalline was mediated by Sn nanodots formed on SiO2. It was found that introduction of Sn is expected to reduce thermal conductivity without degrading other properties, such as electric conductivity and Seebeck coefficient. Inelastic X-ray scattering revealed that the reduction in thermal conductivity is due to the modulation of the local structure, which is observed only in alloy, vibration by Sn atoms.

Free Research Field

結晶成長

Academic Significance and Societal Importance of the Research Achievements

本研究で得られた、Sn導入によって混晶中の局所構造の振動が変調されることを実験的に観測した結果は、混晶の熱電変換素子への応用に向けた材料設計指針の基礎となる知見である。また、安全なSi、Ge、およびSnからなる混晶を組成を制御しながら絶縁膜上に形成する手法は、論理回路などと同一基板上への熱電変換素子の組み込みに不可欠であり、IoTデバイスなどへの本成果の応用が期待される。