Calculation of Thermal Resistance of Tapered Silicon Nanowires with Phonon-Boundary Scattering

Abstract

We present calculated the thermal resistances of tapered core-shell silicon nanowires ( SiNWs) of a few tens of nanometer in radii and 5.0 mu m in length with phonon-boundary scattering. We apply a modified Callaway model for the theoretical calculation of frequency-dependent phonon mean free path. The phonon-boundary scattering is accounted for by reducing the phonon mean free path using Matthiessen's rule, whereas the core-shell structure is treated in a simple analytical model. It is clearly observed that the calculated contribution of the phonon-boundary scattering to the thermal resistance is of the same order of magnitude as the bulk phonon contribution at near-ambient temperature, and it becomes large at low temperatures.