Crack-free TiO2 films prepared by adjusting processing parameters via liquid phase deposition technique

Abstract

TiO2 thin films with controllable morphology and grain size were prepared via a liquid phase deposition (LPD) technique. The effects of the processing parameters including the (NH4)2TiF6 concentration, solution pH, and (NH4)2TiF6:H3BO3 molar ratio on the grain size and morphology of the films were investigated. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, and ultraviolet–visible spectroscopy. The results showed that the deposition parameters significantly affected the growth and nucleation velocities of the crystalline grains, which resulted in the formation of TiO2 films with different morphologies and grain sizes. The capillary stress among the grains of the film, which resulted in the cracking of the film, depended on the size of the grains. Thus, the cracking of the LPD-derived TiO2 films could be mitigated by adjusting the deposition parameters.