Ultrasmooth Ru(0001) Films as Templates for Ceria Nanoarchitectures
Single crystalline magnetron sputter deposited Ru(0001) epitaxial thin films on c plane sapphire were prepared and used as a template for reactive CeO2 growth. Low energy electron microscopy and diffraction, as well as transmission electron microscopy and atomic force microscopy, experiments were performed to investigate the crystallinity and morphology of the prepared films. Multiple cycles of Ar+ sputtering and high temperature annealing produces films of exceptional surface quality. High temperature reactive ceria growth leads to perfectly aligned triangular single crystalline CeO2(111) islands of extraordinary morphological and structural homogeneity. At the chosen growth conditions, ceria nucleation takes place only at V shaped surface defects on the otherwise atomically flat Ru terraces, opening up the possibility to influence the nucleation by introducing artificial surface defects using standard etching techniques. Due to their high crystallinity and extraordinary surface quality, these substrates.