Quantitative growth studies using surface diffraction and scanning tunneling microscopy are carried out to determine the intercalation conditions for Pb under Gr/SiC, with initial phase a mixture of buffer-layer and single-layer graphene. Intercalation is a kinetically complex, multistage process with intercalated Pb moving between different subsurface locations with annealing, eventually to the location of higher stability. The transfer is determined by monitoring the difference of a given spot intensity from its clean value, as a function of growth parameters. In addition, a broad, low-intensity ${(10\times 10)}_{\mathrm{gr}}$ moiré phase is observed exclusively originating from intercalated Pb. Well-defined growth conditions are identified for the moiré spot to be observed reversibly. The ${(10\times 10)}_{\mathrm{gr}}$ phase follows changes of the Pb(10) spot during growth and annealing experiments, instead of changes of the other Gr/SiC spots indicating preferred nucleation of Pb islands on the ${(10\times 10)}_{\mathrm{gr}}$ domains. These structural results are discussed in connection to different models proposed for the ${(10\times 10)}_{\mathrm{gr}}$ supercell and the subsurface Pb coverage. Mass transport of subsurface Pb is unusually high, possibly because of the very high compression of the intercalated Pb, when compared to metallic Pb(111).

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• Graphene
• Surfaces
• Thin films