In order to ascertain the heat dissipation performance of high-power gallium nitride devices, the thermal transport characteristics of GaN/graphene/diamond heterostructures are investigated at heterogeneous interfaces through molecular dynamics simulations. This study focuses on phonon transport mechanisms and regulatory strategies in the interfacial regions. The key findings are summarized below.

Comparative analysis of two contact configurations reveals that the Ga-C structure exhibits an interfacial thermal conductance three times higher than that of the N-C structure, which is attributed to its larger phonon cutoff frequency and enhanced interfacial phonon coupling as evidenced by phonon spectral analysis. The intrinsic heterostructure demonstrates no thermal rectification characteristics without interface engineering. The analysis of hydrogenation effects shows that although hydrogenation generally hinders interfacial heat transfer, the thermal conductance increases paradoxically with the increase of hydrogenation ratio. This counterintuitive phenomenon arises from hydrogen-induced lattice disorder/hybridization scattering causing phonon localization (particularly severe in GaN-side hydrogenation), while generating new phonon coupling channels. The elemental doping investigations show that nitrogen and boron doping leads to an initial increase and subsequent decrease in interfacial thermal conductance, while silicon doping produces monotonic enhancement. Overlap factor analysis indicates that N and B doping first strengthens then weakens interfacial phonon coupling, whereas Si doping significantly improves coupling through synergistic effects of strong interfacial interactions and phonon focusing. Comparative evaluation of two Si doping potential functions shows that the difference in thermal conductance results is negligible. The studies on doping morphology show that although linear doping configurations can cause systematic changes in graphene phonon spectra, their influence on interfacial thermal conductance is minimal.

These findings offer critical theoretical insights into thermal management optimization of GaN-based devices and provide fundamental guidance for overcoming thermal dissipation bottlenecks in high-power electronic systems.