Co on h-BN/Ni(1 1 1): from island to island-chain formation and Co intercalation

The growth of cobalt on a monolayer of hexagonal boron nitride on Ni(1 1 1) has been studied in a combination of scanning tunneling microscopy and X-ray photoelectron spectroscopy (XPS). A detailed picture of the growth kinetics is obtained. The Co sticking coefficient strongly decreases at high substrate temperatures. Co deposition results in two different morphologies: (i) three-dimensional clusters that grow on top of the hexagonal boron nitride (h-BN) film and often align themselves to form chains and (ii) islands with a more two-dimensional character, which are intercalated below the h-BN film dominate at higher substrate temperatures. From XPS measurements at different deposition temperatures an activation energy for intercalation of ∼0.24 eV is inferred. The influence of observed defect lines in the h-BN overlayer on the growth kinetics is discussed.