Sr2TiO4 layered perovskite thin films grown by pulsed laser deposition

We have fabricated epitaxial Sr2TiO4 thin films on SrTiO3 (100) single crystal substrates by pulsed laser deposition. We demonstrate that growth parameters including substrate temperature, oxygen pressure, as well as the laser fluence have to be chosen precisely to obtain stoichiometric well-ordered films of this complex layered structure. Films grown at low temperature showed three-dimensional random distribution of SrO double layers, causing a new extinction rule in x-ray diffraction. Stoichiometric Sr2TiO4 films with well-ordered SrO double layers were fabricated at higher temperature and under low oxygen pressures, where thermal energy was sufficient to compensate local composition fluctuation and Sr deficiency was very small.