Growth of SrCuO2 Thin Films on Oxygen-Annealed SrTiO3 (100) Substrates

The effect of annealing on the surface of SrTiO3 (100) substrates and initial growth of SrCuO2 thin films on the SrTiO3 were studied by reflection high-energy electron diffraction (RHEED) and atomic force microscopy (AFM). The terraces of SrTiO3 (100) substrates annealed at 1000° C in O2 atmosphere has atomically flat surfaces with high crystallinity and steps one unit cell high (3.9 Å) . The deposition of SrCuO2 on the annealed substrates forms islands near the steps with a height of 4–7 Å resulting in surface roughening in spite of the flat substrate surface. By depositing Sr as a buffer layer on the annealed substrates, the flatness of SrCuO2 thin films was improved.