Growth of Erbium Silicide Nanowires on Si(001) Surface Studied by Scanning Tunneling Microscopy

Abstract

In this study, we explore the formation and evolution of erbium silicide nanowires on a Si(001) surface under different experimental conditions. Both annealing temperature and Er coverage have effects on the growth of nanowires. It is found that low annealing temperatures of 600–650 °C and low Er coverage [Θ<1.2 monolayer (ML)] lead to the formation of Er silicide nanowires with a AlB2-type crystalline structure; however, high annealing temperatures of 680–700 °C or high Er coverage induces the appearance of nanoislands of rectangular shape. At the late stage, the growth of Er silicide nanowires undergoes Ostwald ripening and this ripening is mainly limited by surface diffusion. The Si atoms in the chemical reaction involved in forming Er silicide nanowires mainly come from the surface step edges of the substrates. However, for the Er silicide nanoislands, the Si atoms on the substrate terraces are consumed in the reaction.