the reduction of the si sublimation rate provided by the current geometry too much si would escape at this temperature resulting in very thick and inhomogeneous graphene by controlling the si sublimation rate precise control of the graphene growth and thickness at relatively high temperature is achieved fig3 c displays an afm image and 6 u221a 3 u00d7 6 u221a 3 reconstruction leed pattern of a single layer of graphene grown in this way the terrace edges become less smooth compared with the sic shown in panel b indicating that thermal decomposition of graphene does not necessarily follow the substrate morphology other characteristic features of graphene grown using the instant method are pits and curving steps pits have been proposed to be formed when the domains of the carbon rich surface the precursor of graphene layers grown on sic pin the decomposing surface steps 21 for comparison single layer graphene made by the conventional thermal decomposition method as described in detail in ref 13 is also characterized by afm and leed as shown in fig3 d the density of pits and the homogeneity of single layer graphene domains are significantly increased and decreased respectively compared with the sample prepared using the face to face method graphene grown with both methods show the same lattice constant as extracted from the distance between leed.