Epitaxy of Pt thin films on (001) MgO—II: Orientation evolution from nucleation through coalescence

Orientation selection and microstructural evolution of thin platinum films deposited on to (001) MgO substrates are examined experimentally. The Pt/MgO system is an example of epitaxy in the absence of strong chemical interactions between film and substrate. Platinum films grow in the Volmer-Weber mode of epitaxy, and more than one epitaxial film orientation is possible on (001) MgO depending upon the deposition conditions. Experimental observations of orientation selection during film growth are explained based on film/substrate interface energy and film surface energy minimization. The results indicate that the final microstructure is controlled by grain boundary motion during and after coalescence of the island films.