Young's modulus and ferroelectric property of BaTiO3 films formed by aerosol deposition in consideration of residual stress and film thickness

Film thickening by aerosol deposition (AD) is effective for the fabrication of self-sustained piezoelectric energy harvesting devices. Here we investigated the properties, microstructure, and residual stresses of BaTiO3 films deposited by AD at different film thicknesses. The Young's modulus measured by the nanoindentation test showed no thickness dependence; however, it increased from approximately 130- 160 GPa with annealing. Ferroelectric hysteresis curves showed that the increase in film thickness facilitated polarization switching. The microstructure of the films showed no significant changes with the film thickness, while the results of X-ray diffraction and finite element analysis of thermal stress showed that the residual stress after annealing depended on the film thickness. The energy harvesting performance of the BaTiO3 films deposited by AD may increase owing to the residual stress, rather than the increase in the film thickness.