The effects of grain size and grain boundary characteristics on the thermal conductivity of nanocrystalline diamond

David Spiteri, Julian Anaya Calvo, Martin Kuball

Research output: Contribution to journalArticle (Academic Journal)peer-review

19 Citations (Scopus)

Abstract

Molecular dynamics simulation was used to study the effects of each grain dimension and of grain boundary characteristics on the inter-grain thermal boundary resistance (TBR) and intragrain thermal conductivity of nanocrystalline diamond. The effect of the grain boundaries perpendicular to the heat flow was studied using a multiple slab configuration, which greatly reduced the artifacts associated with the heat source/sink. The TBR between the slabs was found to be more sensitive to the atomic arrangement at the boundary than to the tilt angle between the slabs. When the atomic arrangement at the interface was altered from the minimum energy configuration, the TBR increased by a factor of three, suggesting that a sub-optimal interface quality between the grains could play a large role in reducing the thermal conductivity of nanocrystalline diamond. The thermal conductivity between the boundaries was found to be similar to the bulk value, even when the boundaries were only 25nm apart. The effect of grain boundaries parallel to the heat flow was found to have a large dependence on the microstructural details. Parallel boundaries which were 2nm apart reduced the thermal conductivity of defect-free diamond by between one third and a factor of ten.
Original languageEnglish
Article number085102
Number of pages7
JournalJournal of Applied Physics
Volume119
Issue number8
Early online date25 Feb 2016
DOIs
Publication statusPublished - 28 Feb 2016

Structured keywords

  • CDTR

Keywords

  • thermal conductivity
  • nanocrystalline
  • diamond
  • grain boundaries
  • interface structure
  • molecular dynamics

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    Susan L Pywell (Manager), Simon A Burbidge (Other), Polly E Eccleston (Other) & Simon H Atack (Other)

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