Thermal conductivity of Si-Ge superlattices

S. M. Lee, David G. Cahill, Rama Venkatasubramanian

Research output: Contribution to journalArticlepeer-review


The thermal conductivity of Si-Ge superlattices with superlattice periods 30<L<300 Å, and a Si0.85Ge0.15 thin film alloy is measured using the 3ω method. The alloy film shows a conductivity comparable to bulk SiGe alloys while the superlattice samples have a thermal conductivity that is smaller than the alloy. For 30<L<70 Å, the thermal conductivity decreases with decreasing L; these data provide a lower limit to the interface thermal conductance G of epitaxial Si-Ge interfaces: G> 2 × 10 W m-2 KT-1 at 200 K. Superlattices with relatively longer periods, L> 130 Å, have smaller thermal conductivities than the short-period samples. This unexpected result is attributed to a strong disruption of the lattice vibrations by extended defects produced during lattice-mismatched growth.

Original languageEnglish (US)
Pages (from-to)2957-2959
Number of pages3
JournalApplied Physics Letters
Issue number22
StatePublished - Jun 2 1997

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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