Optimised atomic-level bonding at SiC/graphene heterointerface for enhanced thermal conductivity

High-density power electronics requires efficient thermal substrates to dissipate heat and extend the lifespan of devices. In this study, a high-thermal-conductivity SiC/graphene heterostructure was successfully fabricated by vacuum brazing using AgCuTi filler. A nanoscale transition layer was formed at the brazed joint, achieving atomic-level bonding with both the substrates. Based on interatomic bonding effects, highly efficient phonon transport channels were formed in the joint region, significantly enhancing the directional heat flow and overall thermal transmission efficiency. The SiC/graphene heterostructure substrate showed high thermal performance with an in-plane thermal conductivity of 201.59 W/(m·K), which is 40 % higher than that of unmodified SiC. The peak heating rate of the brazed sample, 1.8 °C/s, is nearly 300 % higher than that of unmodified SiC. Thus, surface modification of SiC heat-dissipation substrates with graphene offers a novel approach for developing multifunctional thermal substrates.