Non-monotonic heat dissipation phenomenon in close-packed quasi-2D and 3D hotspot system

TL;DR

This paper investigates transient heat dissipation in close-packed quasi-2D and 3D hotspot systems, revealing a non-monotonic relationship between heat dissipation efficiency and source spacing due to competing phonon transport processes.

Contribution

It uncovers the counter-intuitive non-monotonic heat dissipation behavior related to phonon mean free path in nanoscale hotspot systems.

Findings

Maximum heat dissipation occurs when source distance is comparable to phonon mean free path.

Heat dissipation efficiency is not simply better with closer sources.

Competition between quasiballistic transport and phonon scattering explains the phenomenon.

Abstract

Transient heat dissipation in close-packed quasi-2D nanoline and 3D nanocuboid hotspot systems is studied based on phonon Boltzmann transport equation. It is found that, counter-intuitively, the heat dissipation efficiency is not a monotonic function of the distance between adjacent nanoscale heat sources: the heat dissipation efficiency reaches the highest value when this distance is comparable to the phonon mean free path. This is due to the competition of two thermal transport processes: quasiballistic transport when phonons escape from the nanoscale heat source and the scattering among phonons originating from adjacent nanoscale heat source.