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Dissertation
Integrated non-planar ferroelectric nanostructures
Doctor of Philosophy (Ph.D.), Drexel University
Apr 2010
DOI:
https://doi.org/10.17918/etd-3260
Abstract
Ferroelectrics (FEs) exhibit stable spontaneous polarization states in the absence of an applied electric field, analogous to other ferroic systems such as ferromagnetics and ferroelastics. Incomplete screening of surface charges along the FE-electrode interface creates a potential gradient across the FE layer. This yields a depolarizing field which greatly suppresses polarization, particularily in systems approaching finite sizes, where surface and interface effects exhibit far more influence than in the bulk. Identifying mechanisms for reducing the detrimental effects of the depolarizing field and maintaining FE stability in finite dimensions remains the largest obstacle in FEs realizing their potential as next generation devices such as electocaloric coolers, actuators, sensors, photovoltaics, and non-volatile memory elements. This thesis aims to develop a reproducible, versatile synthetic approach towards conductive core-ferroelectric perovskite oxide shell nanostructures. A test structure fabrication approach will then be developed, yielding working conductive inner nanowire core electrodes for interrogation of FE properties across the finite (radial) dimension. Here, mapping of the normal ferroelectric polar components within low dimensional FE, with consideration of surface chemical environment effects will be explored. The effects of finite-curvature and its resulting stress gradients in stabilizing ferroelectricity at the nanoscale will also be identified and explored. The nonvolatile gating effects of the FE layer on the transport properties of a low-dimensional semiconductor channel will be investigated. Finally, FE switching will be correlated with system leakage currents, and the effects of oxygen partial pressure, as basis for potential resistive switching memories.
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Details
- Title
- Integrated non-planar ferroelectric nanostructures
- Creators
- Stephen Sommers Nonnenmann - DU
- Contributors
- Jonathan E. Spanier (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Materials (Science and) Engineering (Metallurgical Engineering) [Historical]; College of Engineering (1970-2026); Drexel University
- Other Identifier
- 3260; 991014632422704721