Reconstructing phonon mean-free-path contributions to thermal conductivity using nanoscale membranes

John Cuffe, Jeffrey K. Eliason, A. A. Maznev, Kimberlee C. Collins, Jeremy A. Johnson, Andrey Shchepetov, Mika Prunnila, Jouni Ahopelto, Clivia M. Sotomayor Torres, Gang Chen, Keith A. Nelson

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97 Scopus citations


Knowledge of the mean-free-path distribution of heat-carrying phonons is key to understanding phonon-mediated thermal transport. We demonstrate that thermal conductivity measurements of thin membranes spanning a wide thickness range can be used to characterize how bulk thermal conductivity is distributed over phonon mean free paths. A noncontact transient thermal grating technique was used to measure the thermal conductivity of suspended Si membranes ranging from 15-1500 nm in thickness. A decrease in the thermal conductivity from 74-13% of the bulk value is observed over this thickness range, which is attributed to diffuse phonon boundary scattering. Due to the well-defined relation between the membrane thickness and phonon mean-free-path suppression, combined with the range and accuracy of the measurements, we can reconstruct the bulk thermal conductivity accumulation vs. phonon mean free path, and compare with theoretical models.

Original languageEnglish (US)
Article number245423
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number24
StatePublished - Jun 17 2015

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© 2015 American Physical Society.

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