Highly heteroepitaxial thin films of YBa2Cu3Oy grown on silicon with Eu2CuO4/Y-ZrO2 bi-layer buffer

Highly epitaxial thin films of YBa2Cu3Oy (YBCO) have been grown on silicon with a double buffer of Eu2CuO4(ECO)/Y-ZrO2(YSZ). The utilization of the ECO layer, which possesses a very stable 214-T' structure and excellent compatibility with YBCO, greatly improves the epitaxy and surface morphology of the grown YBCO film, whereas the YSZ layer efficiently blocks the interaction between silicon substrate and YBCO. The grown films were characterized by grazing incidence X-ray reflection, rocking scans of the X-ray diffraction peaks, scanning electron microscopy, cross-sectional transmission electron microscopy, and surface profilometry. The results showed an enhanced crystallinity and very clear interfaces between layers, demonstrating the advantages of such an ECO/YSZ double buffer. It was also found that this bi-layer buffer structure could greatly improve the surface roughness of the YBCO films.