Fluorine as a surfactant in the deposition of a monolayer of Fe on Cu (100)

The deposition of a monolayer of Fe on Cu(100) at 300 K is well known to field a surface that is far from a perfect monolayer of Fe. Both interdiffusion and agglomeration of Fe occur. In the present work, it is found that if the Cu(100) surface is saturated with F atoms prior to the deposition of Fe, most of the interdiffusion and agglomeration of the Fe is suppressed. The surface can then be cooled to 100 K, and the F removed by electron stimulated desorption. This procedure leaves the Fe atoms at the surface frozen in place. The Fe monolayer is not structurally perfect (the LEED spots are broadened), but it appears to be much improved over any other known technique for producing Fe monolayers on Cu(100). A monolayer of high-surface-free-energy metal on low-surface-free-energy substrate may be viewed as a fundamental building block for atomic engineering of novel superlattices. The work reported here is a promising new approach to achieving that end. (C) 1998 Elsevier Science B.V. All rights reserved.