Growth of Ruddlesden-Popper type faults in Sr-excess SrTiO3 homoepitaxial thin films by pulsed laser deposition

Ruddlesden-Popper (R.P.) type faults have been investigated for Sr-excess SrTiO3 (STO) homoepitaxial thin films by pulsed laser deposition (PLD) and tuning of the laser fluence. The R.P. type fault structures were found to depend on the amount of excess Sr. The growth direction of the planer faults changed from normal to normal and parallel to the substrate surface with an increase in excess Sr. Due to the directional change of the planer faults, the out-of-plane lattice shows lattice expansion. The results suggest that we can control the planer fault structures in STO thin films simply by changing the laser fluence in the PLD method.