Role of mechanical strain on thermal conductivity of nanoscale aluminum films

H. F. Lee, S. Kumar, M. A. Haque

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Thin film components of conventional and flexible solid-state devices experience mechanical strain during fabrication and operation. At the bulk scale, small values of strain do not affect thermal conductivity, but this may not true for grain sizes comparable with the electron and phonon mean free paths and for higher volume fraction of grain boundaries. To investigate this hypothesis, thermal and electrical conductivity of nominally 125-nm-thick aluminum films (average grain size 50 nm) were measured as functions of tensile thermo-mechanical strain, using a modified version of the 3-ω technique. Experimental results show pronounced strain-thermal conductivity coupling, with ∼50% reduction in thermal conductivity at ∼0.25% strain. The analysis shows that mechanical strain decreases the mean free path of the thermal conduction electrons, primarily through enhanced scattering at the moving grain boundaries. This conclusion is supported by similar effects of mechanical loading observed on the electrical conduction in the nanoscale aluminum specimens.

Original languageEnglish (US)
Pages (from-to)6619-6627
Number of pages9
JournalActa Materialia
Volume58
Issue number20
DOIs
StatePublished - Dec 2010

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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