Reconstructing phonon mean-free-path contributions to thermal conductivity using nanoscale membranes
Cuffe, John (Massachusetts Institute of Technology. Department of Mechanical Engineering)
Eliason, Jeffrey Kristian (Massachusetts Institute of Technology. Department of Chemistry)
Maznev, Alex A. (Massachusetts Institute of Technology. Department of Chemistry)
Collins, Kimberlee C. (Massachusetts Institute of Technology. Department of Mechanical Engineering)
Johnson, Jeremiah A. (Massachusetts Institute of Technology. Department of Mechanical Engineering)
Shchepetov, Andrey (VTT Technical Research Centre of Finland)
Prunnila, Mika (VTT Technical Research Centre of Finland)
Ahopelto, Jouni (VTT Technical Research Centre of Finland)
Sotomayor Torres, Clivia M. (Institut Català de Nanociència i Nanotecnologia)
Chen, Gang (Massachusetts Institute of Technology. Department of Mechanical Engineering)
Nelson, Keith A. (Massachusetts Institute of Technology. Department of Chemistry)

Data:	2015
Resum:	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.
Ajuts:	European Commission 309150 Ministerio de Economía y Competitividad MAT2012-31392
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Publicat a:	Physical review B : Condensed matter and materials physics, Vol. 91, Issue 24 (June 2015) , art. 245423, ISSN 1550-235X

DOI: 10.1103/PhysRevB.91.245423

Postprint 23 p, 540.5 KB

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