Substantial reduction of thermal conductance (Kph) was recently reported for air gap heterostructures (AGHs) in which two bulk layers were connected by low-density nanopillars. We analyze Kph using a full phonon dispersion and including important phonon scattering. We find a transition from ballistic at low temperatures to quasi-ballistic transport near room temperature and explain the slow roll-off in Kph that occurs near room temperature. We show that the density of nanopillars deduced from the analysis depends strongly on the phonon dispersion assumed. Our model provides a good agreement with experiment that will be necessary to design AGHs for thermoelectric applications


Copyright (2012) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Appl. Phys. Lett. 100, 233109 (2012) and may be found at http://dx.doi.org/10.1063/1.4726111. The following article has been submitted to/accepted by Applied Physics Letters. Copyright (2012) Changwook Jeong and Mark Lundstrom. This article is distributed under a Creative Commons Attribution 3.0 Unported License.

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Analysis of thermal conductance of ballistic point contacts. Changwook Jeong and Mark Lundstrom. Appl. Phys. Lett. 100, 233109 (2012)



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