Growth mechanism of Fe nanoisland array on Cu( [formula omitted])–c(2×2)N surfaces

Abstract

Growth mechanism of Fe nanoisland array is studied on Cu(0 0 1)–c(2×2)N surfaces where 5×5 nm 2 patches of N-adsorbed c(2×2) structure are squarely arranged and separated by a few nm wide lines of clean Cu surface. The correlation between the site of the Fe inclusions in the clean Cu surface and that of the nucleated Fe islands is confirmed using scanning tunneling microscopy. The Fe inclusions effectively act as nucleation centers of the monolayer islands at very low coverage while the sticking process of Fe adatoms to the edge of the islands dominates the island growth at the increased coverage. On the Cu(0 0 1)–c(2×2)N surfaces, preferential island growth at the intersections of the clean Cu lines is ascribed to the large sticking probability. Difference of the surface strain on the clean Cu lines is the origin of the site selections both for the Fe inclusion in the surface and for the sticking probability of mobile Fe adatoms to the edge of the islands.