Graduation Year

2020

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Physics

Major Professor

S. Witanachchi, Ph.D.

Co-Major Professor

P. Mukherjee, Ph.D.

Committee Member

H. Srikanth, Ph.D.

Committee Member

M-H. Phan, Ph.D.

Committee Member

W. G. Matthews, Ph.D.

Keywords

Laser ablation, spatially ordered structures, glancing angle pulsed laser deposition, silica nanosphere monolayers, Zinc Oxide

Abstract

Thin films and nanostructures of functional materials like lead zirconium titanite oxide (PZT) and Zinc Oxide (ZnO) offer multitude of applications in ferroelectrics, piezoelectrics and piezotronics. While the properties of thin films of ZnO and PZT are well understood, methods for the fabrication of vertically-aligned and spatially ordered nanocolumns of these materials are not common. To achieve a spatially ordered arrangement of either PZT or ZnO, a Silica Nanosphere (SNS) Monolayer Template has been constructed to serve as nucleation site for the growth of a specific number of nanocolumns. The SNS monolayer template is constructed by Langmuir-Blodgett dip coating, using SNS’s of diameters ranging from 3800 nm to 160 nm. To understand the nanocolumnar growth ZnO and PZT nanostructures, these were constructed using Glancing Angle Pulsed Laser Deposition (GAPLD), a variation of Glancing Angle Deposition (GLAD) which allows for the columnar growth of materials under proper growth conditions. The structural and morphological properties of these nanostructures were characterized using SEM, EDS and XRD to determine the conditions that showed enhanced crystallinity and correct stoichiometry. To finish the work, ZnO nanostructures were constructed on a SNS monolayer. The physical and structural properties of the ZnO nanostructures on the top surface of each sphere were observed to be dependent on underlying sphere size.

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