Synchrotron X-ray micro-analysis of epitaxial film grown on buffer layer boundary

Ti-doped α-Fe₂O₃ (hematite) film grown on α-Al₂O₃(0001) with structured α-Cr₂O₃ buffer layer was characterized with synchrotron X-ray microdiffraction and fluorescence spectroscopy. Despite of a large lattice mismatch, epitaxial α-Fe₂O₃ film was formed on α-Al₂O₃ bare substrate adjacent to the buffer through mechanism similar to side-wall epitaxy. On bare substrate distant from the buffer only a small portion of film was epitaxial either as coherent to the substrate or strain-relaxed form. The film adjacent to the buffer can be used to fabricate buffer-free epitaxial film attached on a large lattice mismatch substrate.