Adsorption and growth of Xe adlayers on the Cu(111) surface

The adsorption and growth of Xe layers on the Cu(111) surface were studied with a low-temperature scanning tunneling microscope. Initially, Xe atoms preferentially adsorb at the step, revealing two different wetting behaviors at the upper and the lower step edges at the coverage of <0.1 monolayer. Three-dimensional island growth is followed on the terrace at the coverage of >0.2 monolayer when grown at <20 K. The island growth is attributed to inhomogeneous nucleation and lower diffusivity of Xe on the Xe monolayer than on the Cu(111) surface. The diffusion barriers, the two-dimensional barrier on a terrace and the one-dimensional barrier along a step, and the step-down barrier determine the growth morphology of Xe layers as the substrate temperature was raised.