Structural, Electrical, and Optical Properties of Erbium-Doped Epitaxial BaTiO3 Films Grown by RF Sputtering

We have investigated the epitaxial growth of Er-doped BaTiO3 films using rf magnetron sputtering. The Er-doped films (0.5 - 1 μm thick) were deposited on MgO (001) single-crystal substrates at various temperatures (500 - 800 °C). The films deposited at 700 °C or above arehighly (001)- oriented with an in-plane epitaxial relationship of BaTiO3[100] ║ MgO[100], as confirmed by X-ray diffraction. The Er doped films were found to be compressively stressed, as-deposited. The amount of stress monotonically decreases as a function of the deposition temperature. The Er-doped epitaxial films show a strong room-temperature photoluminescence at 1.54 μm, which corresponds to intra-transitions of Er3+ ions. Electrical characterizationswere carried out on Er-doped BaTiO3 films that were grown on MgO with a conducting In203 buffer electrode. The measurement shows that the Er-doped BaTiO3 films are ferroelectric with a remanent polarization of 1.5 μC/cm2 and a coercive field of 40 kV/cm.