Microstructure development and dielectric properties of hydrothermal BaTiO3 thin films

Polycrystalline BaTiO3 thin films were processed hydrothermally by reacting TiO2 films at 90 °C in alkaline solutions containing Ba2+. Films grown on (100) SrTiO3 suggested that BaTiO3 nucleation occurred at the film-substrate interface as well as the film-solution interface. As-reacted BaTiO3 films grown on Pt-coated glass substrates had a dielectric constant and tanδ of 80 and 0.20 respectively. Current–voltage (I–V) measurements suggested that the leakage mechanism combined aspects of Poole–Frenkel and Schottky-barrier controlled processes, and had an associated metal/ceramic barrier height of 0.46 eV. Annealing the BaTiO3 films at 200–500 °C in air resulted in lower values for dielectric constant, tanδ, and leakage current, and a larger barrier height.