Electrical properties of (BaTiO3/SrTiO3)15 superlattices grown by MOCVD

Dielectric multilayers of (BaTiO3/SrTiO3)15 were synthesised on various substrates by a Metal Organic Chemical Vapour Deposition (MOCVD) technique using a pulsed liquid injection source. A single precursor solution was used per compound. The X ray diffraction analysis of the satellite diffraction peaks indicated that the superlattices periodicity can be precisely controlled by the number of injections. Sets of samples were prepared with varying interlayer thickness on doped Nb-SrTiO3 substrates (0.5 atom %). Electrical measurements in the range 20 - 500 K and 20 Hz - 100 kHz were performed on the multilayers, using the STO : Nb substrate as a bottom electrode. As the thickness of the bilayer of the (BaTiO3/SrTiO3)15 superlattices increased (hence the total thickness), the dielectric constant increased as well, reaching values of 650 for (BaTiO3 36 u.c / SrTiO3 36 u.c)15