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.