Nucleation effect of Sia of 6H-SiC-(0 0 0 1)-(√3×√3)R30° surface: First-principles study

First-principles calculations have been performed to investigate the nucleation effect of Si adatoms (Sia) of the 6H-SiC-(0 0 0 1)-(√3×√3)R30° reconstruction surface. The results of C adatoms adsorption energy, Sia desorption energy and the substituting energy of carbon with Sia indicate that the Sia of Si-rich-(√3×√3)R30° reconstruction surface behave as nucleation center in favor of the formation of graphene buffer layer on this surface. The Sia atoms of the reconstruction surface are readily substituted by exotic C atoms, especially when there are carbon adatoms on the surface, which urges the growth of the graphene buffer-layer. The mechanism of the epitaxial growth of graphene on the 6H-SiC-(0 0 0 1) surface was also briefly discussed in our present work.