Self-assembled growth of nanocomposites consisting of TiO2 nanopillars and Pb(Zr0.52Ti0.48)O3 thin films

We report for the first time the self-assembled growth of nanocomposites of 'TiO2 nanopillars on Pb(Zr0.52Ti0.48)O3 (PZT) thin films' using a modified sol-gel processing. Both TiO2 nanopillars and PZT thin films are simultaneously formed during the post-annealing process. The growth behaviours of TiO2 nanopillars are controlled by adjusting the Ti excess amounts of PZT solutions and the post-annealing conditions. The self-assembled growth can be explained on the basis of the combined effects of five factors which can have influence during the annealing process: a Ti ion diffusion to the film surface, a phase separation of PZT and TiO2, a void formation on the film surface, a Ti oxidation at the film surface under oxygen atmosphere, and a nanopillar growth on the film surface.