Growth of platinum ultrathin films on Al2O3(0001)

► In this study we have grown Pt ultrathin films on Al2O3(0001) substrates using sputtering deposition method. ► Pt grows as three dimensional islands on sapphire and we study the size, epitaxial relationship, morphology and strain states of these resulting nano-sized islands. ► Due to the misfit between Pt and Al2O3, the islands undergo an in-plane compression and an out-of-plane tension which relax as the thickness increases.