Optical properties of AlGaN-based deep-ultraviolet LED grown on graphene/SiC

•AlGaN-based DUV LEDs on graphene/SiC substrate with light-emitting bands at 300 nm.•AlGaN-based DUV LEDs on sapphire substrate with light-emitting bands at 275 nm.•The V-shaped pits on the surface of DUV LEDs epitaxially on graphene/SiC promoting the light extraction efficiency.•The luminescence intensity of AlGaN-based DUV LED on graphene/SiC was one order of magnitude higher than that on sapphire.