We investigate technologically relevant ferroelectric materials, mainly the archetypal perovkite BaTiO3 and the recently discovered and highly promising doped HfO2. We grow epitaxial thin films that act as model systems and help determine intrinsic properties and enable device prototypes to be fabricated.

Discovered 100 years ago, ferroelectric materials are receiving renewed interest due to the richness of physical behavior they offer and the recent and unexpected discovery of ferroelectricity in fluorite and wurtzite ceramics. The demonstration of ferroelectricity in HfO2-based oxides is allowing to overcome the bottleneck that represented the low compatibility of classical ferroelectrics with CMOS technology and opens up brilliant possibilities for memory devices and other applications that include energy harvesting.
Our research focuses on thin films of ferroelectric oxides, in particular BaTiO3 and doped HfO2. Pulsed laser deposition and substrate selection enable epitaxial growth with tailored control of crystal phases and lattice strain. Ferroelectric BaTiO3 and HfO2 films are also integrated epitaxially with Si wafers. The impact of growth conditions, electrodes, dopants, lattice strain interfaces and defects is investigated to enhance ferroelectric polarization and reliability (retention, endurance and imprint) of the films. Physical mechanisms determining endurance and switching are investigated. Ferroelectricity is preserved in ultrathin films, allowing the fabrication of ferroelectric tunnel junction devices