Independent control of electric and thermal conductivities by coherent manipulation of electron and phonon transports using three dimensional nanostructures

2014 Fiscal Year Final Research Report

• Project/Area Number: 25600016
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Nanostructural physics
• Research Institution: Osaka University
• Principal Investigator: NAKAMURA Yoshiaki 大阪大学, 基礎工学研究科, 教授 (60345105)
• Co-Investigator(Renkei-kenkyūsha): KIKKAWA Jun 物質・材料研究機構, 先端的共通技術部門, 主任研究員 (20435754)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 熱電ナノ材料 / 半導体 / 分子線エピタキシー / 熱伝導 / ナノドット

Outline of Final Research Achievements

In this study, we aimed at independent control of electric and thermal conductivities using Si films including Ge nanodots, where Si layers and Ge nanodots work as carrier transport layers and phonon scatters, respectively. We formed Si films including epitaxial Ge nanodots using the original ultrathin SiO2 film technique for nanodot formation. As a result, we succeeded in drastic reduction of thermal conductivity with small Ge content compared with conventional SiGe alloy. It was found that the reduction effect depended on the Ge ND size. This means that Ge nanodots dominantly determined the thermal conductivity independently of Si layers for carrier transport. This result gives a guideline for independent control of electric and thermal conductivities.

Free Research Field

ナノ構造