Multi-channel thermal transport mechanisms in high-power GaN-based micro/nano-devices

Multi-channel thermal transport mechanisms in high-power GaN-based systems are critical for advanced thermal management in next-generation electronics due to their wide bandgap, high breakdown electric field, and strong thermal stability. Recent works have highlighted the complex heat dissipation processes in GaN-based systems under high-power operation, prompting significant demands in understanding the underlying principles. Here, we review recent experimental and theoretical progress in thermal transport in high-power GaN-based systems from a multi-channel perspective, with particular emphasis on the coupling among non-equilibrium heat generation, hot electron/phonon dynamics, interfacial thermal transport, size-dependent phonon transport, and additional pathways assisted by surface phonon polaritons. We further discuss how temperature, structural defects, and interface characteristics modulate these transport processes. Finally, current controversies and limitations in research methodologies are addressed, and future research directions are proposed. This review provides a comprehensive understanding of thermal transport mechanisms in GaN-based materials at micro/nano-scale, offering physical insights for advanced heat dissipation strategies.