Study on the Thermal Transport Regulation at GaN/Graphene/Diamond Heterojunction Interfaces

To study the heat dissipation performance of high-power gallium nitride devices, the thermal transport characteristics of GaN/graphene/diamond heterostructures were investigated at heterogeneous interfaces through molecular dynamics simulations. The research focuses on phonon transport mechanisms and regulatory strategies at interfacial regions. The key findings are summarized as follows: 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, 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. Hydrogenation effects analysis demonstrates that while hydrogenation generally impedes interfacial heat transfer, thermal conductance paradoxically increases with hydrogenation ratio. This counterintuitive phenomenon arises from hydrogen-induced lattice disorder/hybridization scattering causing phonon localization (particularly severe in GaN-side hydrogenation), while simultaneously creating new phonon coupling channels. Through elemental doping investigations, nitrogen and boron doping induce initial increases followed by reductions in interfacial thermal conductance, while silicon doping produces monotonic enhancement. Overlap factor analysis indicates that N and B doping first strengthen then weaken interfacial phonon coupling, whereas Si doping significantly improves coupling through synergistic effects of strong interfacial interactions and phonon focusing. Comparative evaluations of two Si doping potential functions show negligible differences in thermal conductance outcomes. Doping morphology studies reveal minimal impact on interfacial thermal conductance, though linear doping configurations induce systematic variations in graphene phonon spectra. These findings provide critical theoretical insights for thermal management optimization of GaN-based devices and offer fundamental guidance for overcoming thermal dissipation bottlenecks in high-power electronic systems.