Fig. 6
Characterizations of GaN films on graphene/SiC. X-ray rocking curves of: a (0002), and b (10\(\bar 1\)2) planes for 2 μm thick GaN films grown on untreated graphene/SiC and nitrogen-plasma-treated graphene/SiC substrates. c Raman spectra of GaN films epitaxially grown on graphene (red) and directly on SiC substrate (black). The green dashed line is the E2 (high) phonon frequency of GaN bulk material under stress-free state
