Control of the morphology of oxide nano-islands through the substrate miscut angle

An experimental method is presented that allows to control the morphology of sol–gel grown epitaxial thin films. Thin films of yttria stabilized zirconia (YSZ) have been grown on two c-cut sapphire substrates by sol–gel dip-coating and epitaxial nano-islands have been formed by high temperature thermal treatment. Atomic force microscopy observations and X-ray diffraction reciprocal space mapping were used to investigate the effects of a step-like structure of the wafer surface on the morphology and on the out-of-plane orientation of epitaxial nano-islands. In all cases investigated the (002) planes of YSZ remained parallel to the (0001) planes of sapphire, but tilted by an amount depending on both the out-of-plane lattice mismatch and miscut angle.