Title:
Piezoelectric thin films and nanowires: synthesis and characterization

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dc.contributor.advisor Wang, Zhong Lin
dc.contributor.author Xiang, Shu en_US
dc.contributor.committeeMember Gerhardt, Rosario
dc.contributor.committeeMember Tummala, Rao
dc.contributor.department Materials Science and Engineering en_US
dc.date.accessioned 2011-09-22T17:48:18Z
dc.date.available 2011-09-22T17:48:18Z
dc.date.issued 2011-06-20 en_US
dc.description.abstract Piezoelectric materials are widely used for sensors, actuators and trasducers. Traditionally, piezoelectric applications are dominated by multicomponent oxide ferroelectrics such as lead zirconate titanate (PZT), which have the advantage of high piezoelectric coefficients. Recently, one-dimensional piezoelectric nanostructures such as nanowires of zinc oxide (ZnO) and gallium nitride (GaN) has gained a lot of attention due to their combined piezoelectric and semiconducting properties. The focus of this thesis is to study the processing and electric properties of such piezoelectric thin films and nanostructures for various applications. There is an increasing interest to form thin films of multicomponent ferroelectric oxides such as PZT on three-dimensional structures for charge storage and MEMS applications. Traditional vapor phase deposition techniques of PZT offer poor conformality over threedimensional surfaces due to their reactant transport mechanisms. As an alternative, solgel synthesis may provide new process possibilities to overcome this hurdle but the film quality is usually inferior, and the yield data was usually reported for small device areas. The first part of this study is dedicated to the characterization of the electric properties and yield of PZT thin film derived from the sol-gel process. PZT thin films with good electric property and high yield over a large area have been fabricated. La doping was found to double the breakdown field due to donor doping effect. LaNiO3 thin films that can be coated on a three-dimensional surface have been synthesized by an all-nitrate based sol-gel route, and the feasibility to form a conformal coating over a three-dimensional surface by solution coating techniques has been demonstrated. ZnO and GaN micro/nanowires are promising piezoelectric materials for energy harvesting and piezotronic device applications. The second part of this study is focused on the growth of ZnO and GaN micro/nanowires by physical vapor deposition techniques. The morphology and chemical compositions are revealed by electron microscopy. Utilizing the as-grown ZnO nanowires, single nanowire based photocell has been fabricated, and its performance was studied in terms of its response time, repeatability, excitation position and polarization dependence upon He-Cd UV-laser illumination. The excitation position dependence was attributed to the competition of two opposite photo- and thermoelectric currents originated from the two junctions. The excitation polarization dependence was attributed to the difference in optical properties due to crystallographic anisotropy. Employing the as-grown GaN nanowires, single nanowire based strain sensor is demonstrated, and its behavior is discussed in terms of the effect of strain-induced piezopotential on the Schottky barrier height. en_US
dc.description.degree M.S. en_US
dc.identifier.uri http://hdl.handle.net/1853/41139
dc.publisher Georgia Institute of Technology en_US
dc.subject PZT thin film en_US
dc.subject Physical vapor deposition en_US
dc.subject Sol-gel en_US
dc.subject Photocell en_US
dc.subject Strain sensor en_US
dc.subject MEMS en_US
dc.subject Capacitors en_US
dc.subject GaN nanowire en_US
dc.subject ZnO nanowire en_US
dc.subject Ferroelectric thin film en_US
dc.subject Piezoelectric nanostructures en_US
dc.subject.lcsh Nanowires
dc.subject.lcsh Thin films
dc.subject.lcsh Piezoelectric materials
dc.title Piezoelectric thin films and nanowires: synthesis and characterization en_US
dc.type Text
dc.type.genre Thesis
dspace.entity.type Publication
local.contributor.advisor Wang, Zhong Lin
local.contributor.corporatename School of Materials Science and Engineering
local.contributor.corporatename College of Engineering
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relation.isOrgUnitOfPublication 21b5a45b-0b8a-4b69-a36b-6556f8426a35
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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