Preferential arrangement of uniform Mn nanodots on Si(111)-7 × 7 surface

Under proper growth conditions, ordered and uniform Mn nanodots were fabricated on a Si(111)-7 × 7 surface without the presence of a wetting layer. The Mn nanodots deposited onto the elevated substrates were observed to occupy preferentially on the faulted half unit cells (FHUCs) of the Si(111)-7 × 7 surface. This phenomenon implies that the Mn dots adsorbed on the FHUCs are more stable than those adsorbed on the unfaulted half unit cells (UFHUCs). Within the framework of quasi-equilibrium thermodynamics, the energy difference between adsorption on the UFHUCs and the FHUCs was estimated to be 0.05± 0.01 eV. The intrinsic attractive potential wells on the FHUCs effectively trap the outdiffusion of Mn atoms and consequently result in a preferential arrangement of islands with well-defined sizes.