Dislocation density in SrTiO₃film grown on DyScO₃by pulse laser ablation

SrTiO3films are fabricated on DyScO3substrates by pulse laser deposition. In situ X-ray diffraction (XRD) is used to characterize the thermal expansion coefficient at low temperature. The abnormal behavior in lattice parameter at 80K may be the hint of a phase transition. High resolution XRD is performed to detect the two kinds of dislocations, i.e. screw and edge. Results show that the density of edge dislocation is a little larger than that of the screw one. The total dislocation density has the order of about 10 cm . Edge dislocation density decreases with the increase of the film thickness. We argue that the ratio between these two dislocation densities results in the growth mode of the film.