ZnO-BaTiO₃ vertically aligned nanocomposite (VAN) thin films with tailorable morphology and functionalities

ZnO-based nanocomposites have been shown to possess unique properties that make them suitable for various electronic and optical applications. ZnO is a well-known piezoelectric material. Coupling it with another oxide with ferroelectric and piezoelectric behavior could lead to a composite thin film for sensing and data storage applications. In this study, ZnO-BaTiO₃ (BTO) nanocomposites in the form of vertically aligned nanocomposite (VAN) thin films were synthesized, and the impacts of pulsed laser deposition (PLD) laser frequency and substrate selection on the piezoelectric and ferroelectric properties were explored. Tuning the laser frequency changes the adatom diffusion length and therefore the VAN pillar diameters. Similarly, different substrates can vary the growth orientations and morphologies of the two phases in VANs due to different lattice structures between the two film phases and the substrate, enabling tuning of strain and properties. Overall, this study demonstrates the potential of ZnO-BTO VAN thin films for sensor applications because of their inherent piezoelectric and ferroelectric properties.