Barium titanate films synthesized by an anodic oxidation-based electrochemical method

Abstract

Barium titanate films were synthesized by anodic oxidation galvanostatically in an electrolyte of 0.5 M Ba(CH 3COO) 2 with 2 M NaOH. The films were first prepared using a wide constant current range from 5 to 40 mA. XRD results showed that rutile TiO 2 was present at 10 mA and cubic BaTiO 3 films could be obtained at currents over 20 mA. The Ti anodes were then electrolyzed at constant current of 30 mA with various deposition times from 0.5 to 4 h. XRD results showed that TiO 2 existed at 0.5 h and BaTiO 3 appeared at electrolytic times over 0.75 h. From the XRD results associated with the variations of electrolytic voltage with time, rutile TiO 2 has been found to be a precursor for the formation of BaTiO 3. BaTiO 3 films with uniformly distributed small grains were formed at voltages over 60 V and below the dielectric breakdown voltage. The formation mechanism could be due to dissolution and crystallization. BaTiO 3 films with large crater shaped grains were present when voltages reached a dielectric breakdown voltage, which could be due to anodic spark deposition.