Besides thermodynamic and morphological aspects, the chemistry at the SiC surfaces is also relevant, especially the role of carbon. Our growth conditions (1100-1500 °C, 7000 Pa and hydrocarbon by-product to hydrogen ratio in the order of 135 to 406 ppm, assuming 1 to 3 mole of ethylene (C2H4) per mole of TEB ) seem to be adequate for the growth of graphene at the 4H-SiC(0001) surface .