On the formation mechanism of Ba0.85Ca0.15Zr0.1Ti0.9O3 thin films by aqueous chemical solution deposition

Abstract

Here we report on the development of an environmentally friendly, simple and robust aqueous chemical solution route for the fabrication of Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) thin films. Using a stable aqueous precursor solution, thin films were prepared by spin coating and the impact of thermal processing on the microstructure and phase purity of the thin film was revealed by X-ray diffraction and transmission electron microscopy. We find, that barium oxycarbonate formation during the pyrolysis plays a key role in the formation of dense, homogeneous single phase BCZT films. The formation of barium oxycarbonate leads to undesirable segregation of cations, resulting in barium depletion on the BCZT grain boundaries and occurrence of a secondary phase (CaZrTi2O7). Based on this insight the thermal processing was optimized and dense, oriented and single-phase BCZT films were fabricated by combining a low pyrolysis temperature with rapid heating to the annealing temperature.