Photochemical Reactivity of Titania Films on BaTiO3 Substrates: Influence of Titania Phase and Orientation

Titania films were grown on BaTiO3 (BTO) substrates by pulsed laser deposition to create (001)(Anatase)parallel to(100)(BTO), (100)(Rutile)parallel to(111)(BTO), and (110)(Rutile)parallel to(110)(BTO) heterostructures. The photochemical reactivity was evaluated by observing the amount of silver reduced by each film under identical conditions. The thickest films (100 nm) had reactivities that varied with the phase of titania and the crystal orientation. Thin films (15 nm), on the other hand, had reactivities that were approximately the same. Furthermore, reaction products were spatially distributed in patterns consistent with the underlying domain structure of the substrate. For the case of (110)(Rutile)parallel to(110)(BTO), the thin films are more reactive than the thick films, showing that the dipolar Fields in the ferroelectrie substrate enhance the reactivity of (110) rutile.