ERA

Download the full-sized PDF of Characterization and modification of obliquely deposited nanostructuresDownload the full-sized PDF

Analytics

Share

Permanent link (DOI): https://doi.org/10.7939/R3D66X

Download

Export to: EndNote  |  Zotero  |  Mendeley

Communities

This file is in the following communities:

Graduate Studies and Research, Faculty of

Collections

This file is in the following collections:

Theses and Dissertations

Characterization and modification of obliquely deposited nanostructures Open Access

Descriptions

Other title
Subject/Keyword
porosimetry
focused ion beam
nanostructure
glancing angle deposition
Type of item
Thesis
Degree grantor
University of Alberta
Author or creator
Krause, Kathleen
Supervisor and department
Brett, Michael (Electrical and Computer Engineering)
Examining committee member and department
Nychka, John (Chemical and Materials Engineering)
Thomson, Douglas (Electrical and Computer Engineering)
McMullin, James (Electrical and Computer Engineering)
Sit, Jeremy (Electrical and Computer Engineering)
Department
Department of Electrical and Computer Engineering
Specialization

Date accepted
2011-03-01T21:19:32Z
Graduation date
2011-06
Degree
Doctor of Philosophy
Degree level
Doctoral
Abstract
The glancing angle deposition (GLAD) technique is now used by over one hundred research groups, each requiring a fundamental understanding of and new techniques for modulating the properties of GLAD in order to optimize their results. In this thesis, the structural characteristics of nanostructured columnar films were therefore investigated and quantified using gas adsorption porosimetry, focused ion beam tomography, optical methods, scanning electron microscopy (SEM) image analysis. Questions such as ``What is their surface area?'', ``How porous are they?'', ``How do the films evolve as they grow?'', and ``Can the structural characteristics be manipulated?'' were answered. Surface areas, determined from krypton gas adsorption, were found to be high, making GLAD promising for applications requiring large and rough surface interfaces. Specifically, peak specific surface areas of 700 +/- 150 m^2g^{-1}, 325 +/- 40 m^2g^{-1}, 50 +/- 6 m^2g^{-1} were measured for silica (SiO_2), titania (TiO_2) and indium tin oxide (ITO), respectively. Broad pore distributions, with peaks in the low mesoporous regime of 2 nm to 5 nm, were also determined. The internal surface area may also be up to three times as high as that of the externally exposed surface. As well, despite the fact that GLAD column broaden as they grow, the surface area increases linearly with film thickness. Focused ion beam milling, with concurrent SEM imaging, was then employed to investigate and reconstruct the three-dimensional structure of GLAD films in the tens of nanometers regime not measurable by krypton gas adsorption porosimetry. The measured growth scaling trends agreed with previous findings, but were determined using only one sample, instead of multiple samples of increasing thickness. Mean column diameters, center-to-center spacings, void spacings, and column densities were found to scale with thickness as w = (9.4 +/- 3.0) t^{0.35 +/- 0.09} nm, c = (24.8 +/- 5.2) t^{0.31 +/- 0.08} nm, v = (15.2 +/- 3.8) t^{0.25 +/- 0.06} nm, and d = (3400 +/- 2500) t^{-0.65 +/- 0.15} columns um^{-2}, respectively. Finally, spatially graded nanostructures were demonstrated by extending the GLAD technique to include macroscopic shadowing. Optically transparent, graded thickness and pitch helical films were fabricated with polarization selectivity over a spatial range of 30 mm, concurrent with 70 nm spectral tunability. These structures will be useful for tunable frequency photonic devices.
Language
English
DOI
doi:10.7939/R3D66X
Rights
License granted by Kathleen Krause (katiek@ualberta.ca) on 2011-02-23T02:49:02Z (GMT): Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of the above terms. The author reserves all other publication and other rights in association with the copyright in the thesis, and except as herein provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
Citation for previous publication

File Details

Date Uploaded
Date Modified
2014-05-01T00:33:02.105+00:00
Audit Status
Audits have not yet been run on this file.
Characterization
File format: pdf (Portable Document Format)
Mime type: application/pdf
File size: 97244517
Last modified: 2015:10:12 12:57:45-06:00
Filename: Krause_Kathleen_Spring 2011.pdf
Original checksum: ed7d94dd746474346e99ee27620b2a2c
Well formed: true
Valid: true
Status message: Too many fonts to report; some fonts omitted. Total fonts = 1382
Page count: 358
Activity of users you follow
User Activity Date