Dislocation density and strain distribution in SrTiO₃film grown on (1 1 0) DyScO₃substrate

High quality SrTiO3thin film on (1 1 0) DyScO3substrate is grown by laser molecular beam epitaxy. The lattice strain resulting from the lattice mismatch between the substrate and the film relaxes gradually with depth. A critical thickness of about 30 nm for sharp strain relaxation is observed. The dislocation density, which forms to relax the lattice strain, is estimated to be about 108cm-2according to the high resolution x-ray diffraction. The edge dislocation density is slightly larger than that of the screw ones.