Enhanced thermal transport in GaN nanostructure via directional thermal channeling generated by densely packed heat sources

Abstract

Thermal transport at the nanoscale is critical for thermal management in emerging electronics. As transistor scaling reduces heat source spacing below the phonon mean free path in bulk materials, densely packed heat source configurations exhibit quasi-ballistic transport regimes. Here, we employ nonequilibrium molecular dynamics to simulate the thermal transport characteristics of densely packed GaN heat source nanostructures under varying thickness, duty cycle, periodic conditions, and temperature differences. The results demonstrate that across all parameter ranges investigated in this work, the densely packed heat source configurations exhibit significantly higher thermal conductivity than thin films of the same material and equivalent thickness, achieving a maximum value of 13.04 W m⁻¹ K⁻¹, nearly double that of thin films. This enhancement is mediated by the formation of directional thermal channels through inter-source phonon scattering. By employing a multiscale methodology combining phonon density of states analysis, spectral energy density characterization, and Fourier thermal conduction simulations, we systematically elucidate the governing mechanisms of inter-source phonon scattering from both microscopic and macroscopic perspectives. This research discusses the directional control characteristics of phonon transport in systems with multiple heat source interactions, providing theoretical guidance and references for thermal regulation of field effect transistors.