Source of carbon atoms containing no carbon clusters

Equilibrium Nucleation, Growth, and Thermal Stability of Graphene on Solids

“…To obtain graphene on Pt(III), both benzene and a calibrated carbon atom flux were employed [26]. Figure 3 displays graphically the variation of carbon Auger signal intensity with the time of carbon atom adsorption at T = 1475 K. We readily see that during ~120 s carbon atoms do not accumulate on the surface of platinum (the Auger signal is below the noise level) but dissolve instead actively in its bulk; indeed, desorption can be excluded from consideration because carbon atoms desorb from metal surfaces at high temperatures T > 1900 K [ 27].…”

“…This suggestion is corroborated by our studies of intercalation of graphene layers on a metal with foreign atoms and C 60 fullerene molecules [41], the situation where adatoms build up spontaneously, and in sizable amounts, under the graphene layer, and, thus, force the layer away from the surface of the metal to a distance comparable with the diameter of the intercalated atoms or molecules. Apart from this, experimental studies of surface migration of Si atoms on Ir(III) revealed that the kinetics of surface diffusion under a graphene layer remains the same as on a pure metal [63]. Graphite is known to have layered structure with a large interplanar distance, 2R vdW = 3.35 Ǻ, accounted for by van der Waals coupling without electron exchange.…”

Interaction of Be atoms with (111) Ir surface.

“…It has been shown earlier [3,4] that interaction of many p-elements with faces of refractory metals, which have a pronounced atomic relief, for example, with the faces (100) of BCC-and HCP-lattices, leads to formation of specific adsorption states behaving as surface chemical compounds (SC): surface carbides, silicides, sulfides. When SC are formed, they substantially modify surface properties, in particular, by opening access for subsequent deposited atoms into a substrate bulk, to a dissolved state, by sharply reducing a diffusion barrier for this process [4].…”