Scanning Tunneling Microscopy of the Ytterbium Nanofilm Surface and Layers of Oxygen Molecules Adsorbed on It

Abstract

The surfaces of Yb–Si(111) and O–Yb–Si(111) structures (with a thickness of ytterbium nanofilms of 16 monolayers (6.08 nm)) have been investigated for the first time using scanning tunnel microscopy, which has provided data on the morphology and phase composition of these surfaces. It is found that, prior to oxygen adsorption, the nanofilms exhibit a high degree of homogeneity over their thickness, grow in accordance with a mechanism very close to the layer-by-layer growth, and have a homogeneous crystalline structure. After oxygen adsorption, an island layer of oxygen molecules is formed with a thickness of 0.112 nm. It is shown that the nanofilms morphology in the regions of the film surface coated by a monomolecular oxygen film changes significantly, while the morphology of the surface regions uncoated with the adsorbed layer remains unchanged.