Impact induced adsorption of C on silicon (001) surface

Molecular dynamics simulations were carried out to investigate the adsorption of a low-energy C₂₀ on a reconstructed silicon (001)-(2×12\times1) surface. The impact energies of the C₂₀ fullerene range from 1 eV/atom to 5 eV/atom. After impacting, the C₂₀ molecule is found to move along (011) direction and resides either in the trough or on the dimer at the end of our simulations. The lateral motion of C₂₀ on the surface is dependent on its incident energy. Chemical bonds are formed between C₂₀ and the surface. By the force field analysis, we show that the anisotropic molecule-surface interaction plays the leading role in the lateral motion of C₂₀ as well as its preferable adsorption sites on the dimerized Si surface. These findings are consistent with experimental observations of C₆₀ on Si (001) surface and small carbon clusters on solid surfaces.