BaTiO3 thin films grown on SrTiO3 substrates by a molecular-beam-epitaxy method using oxygen radicals

BaTiO3 (BT) thin films were grown by a molecular-beam-epitaxy method using an oxygen radical source. BaO and TiO2 layers were alternately deposited on SrTiO3 (001) (ST) substrates, and the structure of the thin films obtained was evaluated by x-ray diffraction, reflection high-energy electron diffraction, transmission electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. The BT thin films were oriented in the [001] direction and epitaxially grown without misfit dislocations. The lattice constants of the thin films varied with distance from the interface of BT and ST. Near the interface the alpha value was shorter than that for bulk BT while the c value was longer than that for bulk BT. The surface analysis indicated that adsorbed oxygen was enriched on the BaO-terminated surface in comparison with the TiO2-terminated surface. (C) 1997 American Institute of Physics.