Tuning Lattice Thermal Conductance by Porosity Control in Ultrascaled Si and Ge Nanowires

Abhijeet Paul, NCN, Purdue University
Gerhard Klimeck, NCN, Purdue University

Date of this Version



Applied Physics Letters 98, 083106 (2011)


Copyright (2011) 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. 98, 083106 (2011) and may be found at http://dx.doi.org/10.1063/1.3556648. The following article has been submitted to/accepted by Applied Physics Letters. Copyright (2011) Abhijeet Paul and Gerhard Klimeck. This article is distributed under a Creative Commons Attribution 4.0 Unported License.


Porous nanowires 􏰎NWs􏰍 with tunable thermal conductance are examined as a candidate for thermoelectric devices with high efficiency. Thermal conductance 􏰎􏱆l􏰍 of porous NWs is calculated using the phonon dispersion obtained from a modified valence force field model. Porosity in the NWs break the crystal symmetry leading to the reduction in ballistic 􏱆l. 􏰐100􏰑 Si and Ge NWs show similar percentage reductions in 􏱆l for the same amount of porosity. The model predicts an anisotropic reduction in 􏱆l in SiNWs, with 􏰐111􏰑 showing the maximum reduction followed by 􏰐100􏰑 and 􏰐110􏰑 for a similar hole radius. The reduction in 􏱆l is attributed to phonon localization and anisotropic mode reduction.


Electronic Devices and Semiconductor Manufacturing