▎ 摘　　要

Si3N4 thin films were grown on epitaxial graphene layers on 6H-SiC (0001) substrate, and the related interfacial properties have been studied by using high-resolution transmission electron microscopy (TEM), X-ray photoemission spectroscopy (XPS), and first-principles calculations. It is found that Si3N4 forms uniform coverage on graphene/SiC. The interaction between graphene and Si3N4 is weak, and the measured barrier height between them is 2.7 +/- 0.1 eV, which is high enough to minimize the tunneling carriers. The in situ thermal treatment shows that the Si3N4/graphene/6H-SiC heterojunctions are thermally stable up to 800 degrees C. These results suggest promising application of Si3N4 as a dielectric in graphene-based electronic devices.