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Nonlinear materials responses to external perturbations - in particular when associated with a nonvolatile property that can be read out and manipulated by an applied electric field– are of great interest in today’s ‘More than Moore era’ to embed more functionalities into future optoelectronic devices. Here, ferroelectric oxides play a dominant role, not only because one can switch their permanent polarization, but also because one can find suitable material candidates with a large Pockels coefficient in its vast compositional space that are relevant for efficient electro-optical modulators. The question remains, how these functional materials can be synthesized with excellent stoichiometric control as thin films in a scalable fashion and in a way that their integration with existing material platforms, first and foremost silicon, can be achieved.
In this talk the role of stoichiometry on the ferroelectric properties of strained perovskite thin films, namely CaTiO3, SrTiO3 and BaTiO3 will be discussed. Rather than utilizing commonly employed thin film synthesis approaches for the growth of these complex oxide thin films – namely pulsed laser deposition, sputtering, metal-organic chemical vapor deposition or molecular beam epitaxy – the advantages of a hybrid growth approach combining the advantages of chemical vapor deposition and molecular beam epitaxy are highlighted not only in view of its inherent ability to control cation stoichiometry via a self-regulated growth mechanism, but also because it allows for scalable growth rates while maintaining a self-regulated growth, and the epitaxial integration on silicon. These recent thin film synthesis breakthroughs can accelerate the integration of ferroelectric oxides into existing material platforms and devices.
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