GROWTH AND STRUCTURE OF FE AND CO THIN-FILMS ON CU(111), CU(100), ANDCU(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-r ay-photoelectron and Auger electron forward scattering, CO-titration, low-energy electron diffraction, and reflection high-energy electron d iffraction. 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 betwee n 80 and 450 K plays a prominent role in determining both the film mor phology and crystalline phase. Nonideal film growth, including agglome ration of Co and Fe and surface segregation of Cu, is the rule rather than the exception. Simple considerations of surface diffusion and sur face free-energy differences provide a basis for understanding why lay er-by-layer growth is unlikely to occur in these systems and should no t be expected in many other metastable film-substrate systems.