Growth of La2Ti2O7and LaTiO3 thin films using pulsed laser deposition

The influence of substrate temperature, oxygen activity of the ambient gas, and substrate type on the growth morphology, phase selection, and epitaxy of thin films in the LaTiOx (x approximate to 3.0 or 3.5) family were investigated. The films were deposited using pulsed laser deposition (PLD) from a La2Ti2O7 target and were characterized using X-ray diffraction. In oxygen atmospheres, coupled with high deposition temperatures and use of (1 1 0)-oriented SrTiO3 substrates, the growth of epitaxial films of (1 1 0)-layered perovskite La2Ti2O7 is observed. However, under similar deposition conditions, on SrTiO3(1 0 0) substrates, no crystalline peaks were observed even at the higher temperatures. The reduction of Ti4+ to Ti3+ was achieved by the use of nitrogen atmospheres. This resulted in the formation of the cubic perovskite LaTiO3, on SrTiO3(1 1 0), SrTiO3(1 0 0), and LaAlO3(1 0 0) substrates. (C) 2008 Elsevier B.V. All rights reserved.