Size-Dependent Thermal Boundary Resistance and Thermal Conductivity in Si/Ge Core–Shell Nanowires

Heat transfer through interfaces in nanostructures is becoming ever more important in functional nanodevices. The existence of interface between two dissimilar materials overheats nanoelectronics and impacts heat transfer greatly. It is a challenge how to modulate interface to tailor the thermal transport properties of nanodevices from the perspective of atomic level. In this brief, we consider how size and interface strain affect thermal boundary resistance (TBR) as well as thermal conductivity (TC) of Si/Ge core-shell nanowires (CSNWs) using a thermal kinetic method in terms of atomic-bond-relaxation correlation mechanism and continuum medium mechanics. We propose a theoretical model to pursue the underlying mechanism on the TBR and TC that determined on the core or shell thickness, surface roughness, and interface mismatch. Our approach provides a useful guidance to the theoretical design and experimental control of epitaxial growth in the radial CSNWs for practice applications.

I. Introduction

In the process of miniaturization of electrics and performance improvement, heat dissipation is becoming a major problem [1]. Usually, the existence of thermal boundary resistance (TBR), blocks heat flow transfer [2], suppresses thermal conductivity (TC), and overheats miniature devices [3], [4]. How should we deal with heat dissipation? In fact, interface or boundary engineering is a promising way to modulate TBR and TC for different applications [5], [6].