Atomistic simulations of heat transport in real-scale silicon nanowire devices

TL;DR

This study uses atomistic simulations to analyze heat transport in silicon nanowire devices, revealing how contact interfaces, surface roughness, and wire length influence phonon behavior and thermal conductance.

Contribution

It provides new insights into how contact effects and surface roughness affect thermal transport regimes in real-scale silicon nanowire devices.

Findings

Thermal transport differs significantly from suspended nanowires due to contact scattering.

Surface roughness and length can tune phonon transport from ballistic to diffusive.

Phonon tunneling in short wires enhances conductance beyond single contact levels.

Abstract

Utilizing atomistic lattice dynamics and scattering theory, we study thermal transport in nanodevices made of 10 nm thick silicon nanowires, from 10 to 100 nm long, sandwiched between two bulk reservoirs. We find that thermal transport in devices differs significantly from that of suspended extended nanowires, due to phonon scattering at the contact interfaces. We show that thermal conductance and the phonon transport regime can be tuned from ballistic to diffusive by varying the surface roughness of the nanowires and their length. In devices containing short crystalline wires phonon tunneling occurs and enhances the conductance beyond that of single contacts.