Ferroelectric Thin Films and Nanostructures
Ferroelectric (FE) thin films and nanostructures find a wide range of applications in capacitive elements, non-volatile memories, micro- and nano-electromechanical system (MEMS/NEMS) sensors, actuators and transducers, as well as actively tunable photonic and phononic crystals, and energy harvesting nano- and micro-generators. With the drive towards miniaturization, multiple intrinsic and extrinsic factors need to be leveraged in order to increase and/or maintain the high response of the FEs and reduce size effects.
This presentation will address some of the work currently performed in our group to improve the dielectric and piezoelectric response of ferroelectric ultrathin films (≤ 300 nm in thickness), as well as introduce novel processing techniques for creation of FE nanostructures, enabling new device creation. Specifically, I will discuss optimization of chemical solution deposition of FE thin films in order to obtain dense and highly oriented columnar growth on non-epitaxial substrates, and the effects of chemical heterogeneities on the dielectric and piezoelectric response of FE thin films.
I will also introduce two new techniques developed in Smart Materials and Devices Lab for creation of high- and low-aspect ratio nanostructures, based on chemical solution deposition: soft-template infiltration and thermochemical nanolithography. Additionally, I will discuss size effects and impact of lateral and substrate-induced constraints on the extrinsic contribution to the piezoelectric response in polycrystalline, ferroelectric nanostructures.