ATOMIC-STRUCTURE OF 2-DIMENSIONAL AG LAYER GROWN ON SI(001)-(2X1) AT ROOM-TEMPERATURE

Atomic structures of the two-dimensional Ag layer grown on Si(001)-(2 x 1) at room temperature have been studied by coaxial impact collision ion scattering spectroscopy. After several monolayers of Ag had been deposited on the Si(001)-(2 x 1) surface, the two-dimensional Ag layer was found to consist of Ag dimers. The bond length of the Ag dimer wa s 2.89+/-0.05 Angstrom. The heights of the Ag dimers from the second S i layer were 2.45 and 3.02 Angstrom. The Ag dimers were located in the hollow sites between two dimers along the Si row, and in the middle o f four neighbouring Si dimers with the orientation of the Ag dimer row being perpendicular to that of the Si dimer. Thus, the Si substrate u nder the two-dimensional Ag layer still retained its initial dimer str ucture. Therefore, it was concluded that the two-dimensional Ag layer on Si(001)-(2 x 1) had a Ag(2 x 2) structure with a saturation coverag e of 1 ML. (C) 1998 Elsevier Science B.V. All rights reserved.