Independent control of electrical and heat conduction by nanostructure designing for Si-based thermoelectric materials

Shuto Yamasaka, Kentaro Watanabe, Shunya Sakane, Shotaro Takeuchi, Akira Sakai, Kentarou Sawano, Yoshiaki Nakamura

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)

Abstract

The high electrical and drastically-low thermal conductivities, a vital goal for high performance thermoelectric (TE) materials, are achieved in Si-based nanoarchitecture composed of Si channel layers and epitaxial Ge nanodots (NDs) with ultrahigh areal density (∼1012 cm-2). In this nanoarchitecture, the ultrasmall NDs and Si channel layers play roles of phonon scattering sources and electrical conduction channels, respectively. Electron conductivity in n-type nanoacrhitecture shows high values comparable to those of epitaxial Si films despite the existence of epitaxial NDs. This is because Ge NDs mainly scattered not electrons but phonons selectively, which could be attributed to the small conduction band offset at the epitaxially-grown Si/Ge interface and high transmission probability through stacking faults. These results demonstrate an independent control of thermal and electrical conduction for phonon-glass electron-crystal TE materials by nanostructure designing and the energetic and structural interface control.

Original languageEnglish
Article number22838
JournalScientific reports
Volume6
DOIs
Publication statusPublished - 2016 Mar 14
Externally publishedYes

ASJC Scopus subject areas

  • General

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