Surface Characterization of YBa2Cu3Ox(001) Single-Crystal Substrates for Homoepitaxial Growth

We have evaluated the properties of YBa2Cu3O x (001) single-crystal substrates with areas as large as 10×10 mm. They have good crystallinity with a χ min value of 1.8% determined by Rutherford backscattering spectrometry, grains with areas as large as 5×5 mm confirmed by X-ray topography, and excellent surface morphology with unit-cell steps which were observed by atomic force microscopy. However, approximately one unit-cell-thick degraded layer on the surface, which was observed by angle-resolved X-ray photoelectron spectroscopy, presents problems which must be resolved. These analyses indicate that YBa2Cu3O x single crystal grown by the pulling method is a promising substrate material for homoepitaxial growth.