Observation of the Stranski-Krastanow mechanism during the ultrathin Mo film growth on the sapphire R-plane

Abstract

On the sapphire R-plane, ultrathin Mo films with a thickness of less than 10 nm, which are resistant to oxidation for a long time, were grown. For these films, the appearance of the Stranski-Krastanow type islands was first observed in the thickness range of 1–1.6 nm after the growth process was interrupted. The base diameter of islands and their height were ∼ 100–150 nm and 20–25 nm, respectively. At maximum thickness values in this range (1.6 nm), the island formation was not fully completed, and each large island consisted of a set of smaller ones. In the rest of the thickness range, only the substrate relief was observed in the atomic force microscope (AFM) images, which is typical for two-dimensional film growth.