Systematic studies of periodically nanoporous Si films for thermoelectric applications

Qing Hao, Dongchao Xu, Hongbo Zhao

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations

Abstract

As the major heat carriers in dielectrics and semiconductors, phonons are strongly scattered by boundaries and interfaces at the nanoscale, which can lead to a significantly reduced lattice thermal conductivity h. In recent years, such phonon size effects have been used to enhance the thermoelectric performance of various nanostructured materials. With dramatically reduced kL and bulk-like electrical properties, high thermoelectric performance has been demonstrated for nanoporous Si films at room temperature. Despite these encouraging results, however, challenges still exist in the theoretical explanation of the observed low Ai values. Existing studies mainly attribute the observed low kL to phononic effects and/or amorphous pore edges. These two effects can be separated when the specific heat of the film can be measured along with kL to provide more insight into the phonon dispersion modification. In this work, both the specific heat and t of a suspended nanoporous Si film is extracted from the 3ω measurements. The result is compared to the reported kL values of various porous Si films. The influence of employed phonon mean free path spectrum on the data analysis is discussed.

Original languageEnglish (US)
Title of host publicationNanoscale Heat Transport - From Fundamentals to Devices
PublisherMaterials Research Society
Pages27-32
Number of pages6
Volume1779
ISBN (Electronic)9781510826342
DOIs
StatePublished - 2015
Event2015 MRS Spring Meeting - San Francisco, United States
Duration: Apr 6 2015Apr 10 2015

Other

Other2015 MRS Spring Meeting
CountryUnited States
CitySan Francisco
Period4/6/154/10/15

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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    Hao, Q., Xu, D., & Zhao, H. (2015). Systematic studies of periodically nanoporous Si films for thermoelectric applications. In Nanoscale Heat Transport - From Fundamentals to Devices (Vol. 1779, pp. 27-32). Materials Research Society. https://doi.org/10.1557/opl.2015.707