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Spontaneous Pattern Formation in Photoelectrodeposited Semiconductor Films

Citation

Batara, Nicolas Anthony (2017) Spontaneous Pattern Formation in Photoelectrodeposited Semiconductor Films. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z98S4MZ4. http://resolver.caltech.edu/CaltechTHESIS:06032017-161239736

Abstract

The ability to manipulate matter with ever-increasing precision has enabled the fabrication of nanoscale structures with unprecedented utility. Scalable patterning technologies have dramatically transformed diverse application spaces such as computing and photonics, in part due to diminishing cost per unit area. The work in this thesis presents a template-free, bottom-up technique based on photoelectrodeposition which allows the direct fabrication of periodically nanostructured thin films of semiconductor material over large areas.

First, we examine the effects of wavelength, polarization and incidence angle of illumination on the film morphology. We develop an understanding of the pattern formation to be the result of interference of light scattered across the surface of the growing interface. We also examine the morphological effects of more complex illumination conditions. For example, when deposited under two different illumination wavelengths, the period of patterned films self-optimizes to concentrate light absorption to the tips of the nanostructures . Additionally, we find that the relative polarization angles and phases of two illumination sources can be tuned to produce film morphologies ranging from isotropic mesh-type patterns to orthogonally arranged, intersecting lamellar structures with independent periodicities.

We deepen our understanding of these observations by building a probabilistic computational model that correlates the local light absorption with a local growth probability at the interface of the film with few material parameters. We find that this model is able to reproduce experimentally observed morphological features for all illumination conditions investigated in this work. Through Fourier analysis, we find quantitative agreement between the simulated and experimental periods. Separately, we use electrodynamic simulations on idealized lamellar structures to understand the effect of two coincident illumination sources on the spatial absorption profile.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:nanotechnology; semiconductors; chalcogenide; photoelectrodeposition; electrodeposition; self-assembly; nanophotonics
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Materials Science
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Atwater, Harry Albert (co-advisor)
  • Lewis, Nathan Saul (co-advisor)
Thesis Committee:
  • Atwater, Harry Albert (chair)
  • Lewis, Nathan Saul
  • Greer, Julia R.
  • Bernardi, Marco
Defense Date:24 October 2016
Non-Caltech Author Email:nick.batara (AT) gmail.com
Funders:
Funding AgencyGrant Number
U.S. Department of Energy, Office of Science, Office of Basic Energy SciencesDE-SC0001293
Record Number:CaltechTHESIS:06032017-161239736
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:06032017-161239736
DOI:10.7907/Z98S4MZ4
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1073/pnas.1315539110DOIArticle adapted for Ch. 2
http://dx.doi.org/10.1021/acs.nanolett.5b03137DOIArticle adapted for Ch. 3
http://dx.doi.org/10.1021/acsnano.5b05119DOIArticle adapted for Ch. 4
http://dx.doi.org/10.1021/acs.nanolett.5b04999DOIArticle adapted for Ch. 5
ORCID:
AuthorORCID
Batara, Nicolas Anthony0000-0002-9154-4577
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10262
Collection:CaltechTHESIS
Deposited By: Nicolas Batara
Deposited On:07 Jun 2017 17:24
Last Modified:15 Jun 2017 17:03

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