Thermal transport in porous Si nanowires from approach-to-equilibrium molecular dynamics calculations

X Cartoixa and R Dettori and C Melis and L Colombo and R Rurali, APPLIED PHYSICS LETTERS, 109, 013107 (2016).

DOI: 10.1063/1.4955038

We study thermal transport in porous Si nanowires (SiNWs) by means of approach-to-equilibrium molecular dynamics simulations. We show that the presence of pores greatly reduces the thermal conductivity, kappa, of the SiNWs as long mean free path phonons are suppressed. We address explicitly the dependence of kappa on different features of the pore topology-such as the porosity and the pore diameter-and on the nanowire (NW) geometry-diameter and length. We use the results of the molecular dynamics calculations to tune an effective model, which is capable of capturing the dependence of kappa on porosity and NW diameter. The model illustrates the failure of Matthiessen's rule to describe the coupling between boundary and pore scattering, which we account for by the inclusion of an additional empirical term. Published by AIP Publishing.

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