GROWTH AND STRUCTURE OF FE AND CO THIN-FILMS ON CU(111), CU(100), AND CU(110) - A COMPREHENSIVE STUDY OF METASTABLE FILM GROWTH

The growth and structure of Fe and Co thin films on single-crystal Cu(111), Cu(100), and Cu(110) substrates have been investigated using x-ray-photoelectron and Auger electron forward scattering, CO-titration, low-energy electron diffraction, and reflection high-energy electron diffraction. The motivation for this study is to understand the role of surface structure and kinetics in the growth of metal films on metal substrates. The effect of varying substrate growth temperatures between 80 and 450 K plays a prominent role in determining both the film morphology and crystalline phase. Nonideal film growth, including agglomeration of Co and Fe and surface segregation of Cu, is the rule rather than the exception. Simple considerations of surface diffusion and surface free-energy differences provide a basis for understanding why layer-by-layer growth is unlikely to occur in these systems and should not be expected in many other metastable film-substrate systems.