Diameter dependence of SiGe nanowire thermal conductivity

TL;DR

This paper presents a theoretical study of how the thermal conductivity of SiGe nanowires varies with diameter, alloy concentration, and temperature, aligning well with experimental data and exploring a broad range of compositions.

Contribution

The study provides a comprehensive theoretical analysis of SiGe nanowire thermal conductivity dependence on diameter and alloy composition, extending understanding across the full alloy range.

Findings

Thermal conductivity decreases with decreasing nanowire diameter.

Weaker diameter dependence observed in SiGe compared to pure Si.

Results agree quantitatively with experimental measurements.

Abstract

We theoretically compute the thermal conductivity of SiGe alloy nanowires as a function of nanowire diameter, alloy concentration, and temperature, obtaining a satisfactory quantitative agreement with experimental results. Our results account for the weaker diameter dependence of the thermal conductivity recently observed in Si$_{1-x}$Ge$_x$ nanowires ($x<0.1$), as compared to pure Si nanowires. We also present calculations in the full range of alloy concentrations, $0 \leq x \leq 1$, which may serve as a basis for comparison with future experiments on high alloy concentration nanowires.