Abstract
Properties of ferroelectric oxides are known to be dominated by interface effects at the reduced length scale. This dissertation investigates the various interface effects and domain switching behaviors in ultra-thin crystalline epitaxial (00 I) PbZr0.2Ti0.803(PZT(20/80)) thin films.
In particular, films <20nm in thickness were grown using pulsed laser deposition (PLD) and then characterized using piezoresponse force microscopy (PFM) and x-ray diffraction (XRD).
The thickness chosen is such that the interface-dependent ferroelectric phenomena and their effects are enhanced; namely, imprint and depolarization field. In order to achieve a systematic study, the thesis was divided into three key objectives; the effect of interface band-offset on the as-grown polarization state and surface photochemical reactivity, the domain switching behavior at subcritical field regimes, and the modification of the domain switching environment through the introduction of a dielectric inlay layer.
The collective findings in this study unequivocally demonstrate the fact that interface effects such as electrode-induced imprint and depolarization field, though unavoidable, can be exploited to either unearth or improve functional properties of ultrathin ferroelectric films. This highlights the point, that rather then the conventional approach to circumvent interface-related degradation effects, greater emphasis should be placed on how they can they can be harnessed positively.