Thermal Transport Study on Nanoslot-Patterned Thin Films

Yue Xiao, Qiyu Chen, Qing Hao

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

Abstract

Nanoporous thin films have been extensively studied for their potential applications such as thermoelectrics and thermal management. Different from the popular cylindrical through-film pores, a novel nanoslot pattern design is investigated in this work to achieve better performance in thermal insulation, in-plane thermal anisotropy, and thermoelectrics. In this nanoslot pattern, rectangular pores, or “nanoslots”, are patterned in periodic rows with a narrow neck width between adjacent nanoslots within the same row. Such a narrow neck is the geometric constriction for the phonon transport, resulting in a largely reduced lattice thermal conductivity along the direction perpendicular to the nanoslot rows. In addition, the adjacent rows of nanoslots can also be arranged in an offset manner to further reduce the in-plane thermal conductivity along the same direction, eventually achieving a very high in-plane thermal conductivity anisotropy. Along another line, although the thermal transport is severely suppressed by the nanoslot pattern, the bulk-like electron transport can be largely intact due to the much shorter electron mean free paths compared with the neck width. As a result, the thermoelectric performance can be improved. In this work, frequency-dependent phonon Monte Carlo simulations are utilized to investigate the in-plane thermal conductivity anisotropy of the nanoslot patterns with a maximum room-temperature anisotropy of 37.5 among investigated patterns. Analytical models are also derived to easily predict thermal conductivity and thermoelectric performances. With a neck width reduced to 5 nm, the computed thermoelectric figure of merit can be improved to 0.58 at 1100 K. Potential applications of such nanoslot patterns, such as thermal insulations are heat guides, will also be discussed.

Original languageEnglish (US)
Title of host publicationProceedings of the 20th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2021
PublisherIEEE Computer Society
Pages1233-1240
Number of pages8
ISBN (Electronic)9781728185392
DOIs
StatePublished - 2021
Externally publishedYes
Event20th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2021 - Virtual, San Diego, United States
Duration: Jun 1 2021Jun 4 2021

Publication series

NameInterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM
Volume2021-June
ISSN (Print)1936-3958

Conference

Conference20th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2021
Country/TerritoryUnited States
CityVirtual, San Diego
Period6/1/216/4/21

Keywords

  • Nanoslot
  • Thermal Conductivity Anisotropy
  • Thermoelectrics
  • Thin Film

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering

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