Self-organized formation of regular nanostripes on vicinal surfaces

Abstract

We explore the mechanism of self-organized formation of regular arrays of nanostripes on vicinal surfaces by using a phase-field model. Epitaxial growth during deposition usually results in both nanostripes and islands on terraces of a vicinal substrate. Postdeposition annealing at elevated temperatures induces growth of the nanostripes but makes the islands shrink. It is a ripening process of the mixed system of the nanostripes and the islands, being dependent upon the temperature and strain. It is accompanied by a transition from the diffusion-limited regime to the detachment-limited regime induced by the strain at high temperatures. This ripening makes the islands diminish and on the other hand makes the nanostripes smoother. As a result, the islands disappear completely and the regular arrays of nanostripes are formed on the vicinal substrate. This theory can explain the self-organized formation of nanostripes and nanowires on vicinal surfaces, such as the intriguing regular arrays of Fe nanostripes on the vicinal W surfaces.