Microstructural study of BaTiO3/SrTiO3 superlattice

The microstructure of BaTiO3 (BTO)/SrTiO3 (STO) superlattice grown on (001) STO substrate by laser molecular beam epitaxy (L-MBE) was investigated. The microstructural parameters of BTO/STO superlattice, such as the total film thickness, superlattice period, surface and interface root-mean-square (rms) roughness were obtained by computer simulation of the small-angle X-ray diffraction spectra. The results show that the interfaces and surface of the superlattice are very smooth; their rms roughness is about 2 Å. The experimental examination of atomic force microscopy has proved the smoothness of the surface of the superlattice. There exists a little correlation along 〈001〉 direction of the surperlattice. The growth mechanism of the superlattice is discussed. By modified Braggʹs law, the total thickness of the superlattice is calculated, and is consistent with that of the simulation of small-angle X-ray reflectivity.