Fig. 5

HAADF-STEM analysis of GaN on nitrogen-plasma-treated graphene/SiC. a Cross-sectional HAADF-STEM image of GaN on nitrogen-plasma-treated graphene. b Cross-sectional HAADF-STEM image of the interface area marked with a red rectangle frame in (a). The red arrow points to site where the dark part of the unetched graphene, whereas the blue arrow points to site where the light part of the etched graphene. c, d SAED patterns of AlN on the graphene/SiC marked with a white rectangular frame in (b). e iDPC-STEM image of GaN grown on nitrogen-plasma-treated graphene/SiC. The atomic arrangement of Ga and N atoms confirms the Ga-polarity for the as-grown GaN