Modification of nanoscale morphology and microstructure of heteroepitaxial, 200 nm thick CeO₂ thin films via annealing

Cerium oxide (CeO₂) is often used as a lattice-match cap layer for heteroepitaxial growth of REBa₂Cu₃O_7-x (RE: rare earth) superconductors. In this work, we investigated how the nanostructure and grain size of CeO₂ heteroepitaxial films on biaxially-textured, coated conductor substrates can be modified via annealing in humid, mixed N₂/4%-H₂ gas mixtures. X-Ray diffraction (XRD) analysis shows annealing at higher temperatures shifts the lattice constant to lower values. The full-width-half-maximum (FWHM) of omega and phi scans show that the in-plane and the out-of-plane crystallographic texture is relatively unchanged with post-annealing. Surface reconstruction, roughness and grain sizes were characterized using Atomic Force Microscopy (AFM).