Origin of oxygen induced layer-by-layer growth in homoepitaxy on Pt(111)

Abstract

Whereas on the clean (111) surface Pt grows in a multilayer (3D) mode at 300 and 400 K, preadsorption of an ordered p(2×2) oxygen overlayer leads to a high quality layer-by-layer (2D) growth with the oxygen floating on the film. In contrast to other surfactants oxygen can be completely removed from the film surface at the growth temperature. It is demonstrated that the presence of oxygen reduces the barrier height for the motion of PT adatoms across step edges. This facilitates the interlayer mass transport and thus the layer-by-layer growth.