DFT study of the coverage effects for Al adsorption on Si(1Â 1Â 1) surfaces

► We performed DFT study of the interaction between Si(1 1 1) surface and Al adatoms. ► The threefold-filled adsorption site is the most energy favored at low Al coverage. ► With the increase of Al coverage, Al atomic chains or clusters are formed. ► 1/3 ML Al adsorption surface is semiconducting while the clean surface metallic.