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arXiv · 0902.4735

Impact of Phonon Surface Roughness Scattering on Thermal Conductivity of Thin Si Nanowires

Pierre Martin·Zlatan Aksamija·Eric Pop·Umberto Ravaioli
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Abstract

We present a novel approach for computing the surface roughness-limited thermal conductivity of silicon nanowires with diameter D < 100 nm. A frequency-dependent phonon scattering rate is computed from perturbation theory and related to a description of the surface through the root-mean-square roughness height Delta and autocovariance length L. Using a full-phonon dispersion relation, we find a quadratic dependence of thermal conductivity on diameter and roughness as (D/Δ)^2. Computed results show excellent agreement with experimental data for a wide diameter and temperature range (25-350 K), and successfully predict the extraordinarily low thermal conductivity of 2 W.m^{-1}.K^{-1} at room temperature in rough-etched 50 nm silicon nanowires.

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Pierre Martin, Zlatan Aksamija, Eric Pop, Umberto Ravaioli. 2009-02-27. Impact of Phonon Surface Roughness Scattering on Thermal Conductivity of Thin Si Nanowires. https://doi.org/10.1103/physrevlett.102.125503

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