Modeling and analysis of nanoscale surface patterns produced by broad beam ion bombardment

When a solid surface is exposed to broad beam ion bombardment, nanoscale patterns may spontaneously form. This physical phenomenon is of interest to both the academic and nanofabrication communities. Ion bombardment has the potential to provide a cost-efficient method of producing nanoscale patterns over a large area. As such, it has gathered substantial interest and has been the focus of numerous studies, both experimental and theoretical. However, despite more than half a century of study, there are still many unknowns which limit the application of this method to fabrication. In this dissertation, I present contributions to the field of ion bombarded surfaces (IBS). The first is the development of a Python module which facilitates the rapid production and analysis of simulations. This module provides a well-documented tool to allow collaborators to numerically integrate a user-defined partial differential equation, specifically with IBS in mind. Second is a study of dispersive effects on IBS. Dispersion can lead to the formation of raised and depressed triangular regions traversed by parallel-mode ripples, highly ordered parallel-mode ripples, protrusions and depressions that are elongated along the projected beam direction even when there is no transverse instability, and needle-like protrusions that are visually similar to structures observed in experimental studies. Finally, we applied deep learning techniques to estimate the parameters in the underlying equation of motion from an image of a surface exposed to broad beam ion bombardment at a particular fluence. Our trained neural network will allow experimentalists to quickly ascertain the parameters for a given sputtering experiment.

Name thesis:degree_name

Doctor of Philosophy (Ph.D.)

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Physics

Grantor dc:publisher

Colorado State University. Libraries

Year dc:date.issued

2020

Authors dc:creator

• Loew, Kevin M., author
• Bradley, R. Mark, advisor
• Gelfand, Martin, committee member
• Shipman, Patrick, committee member
• Wu, Mingzhong, committee member

Statement dc:rights

• Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.

Language dc:language.iso

eng, English

Identifier URI

https://doi.org/10.25675/3.02547

OAI identifier oai:identifier

oai:mountainscholar.org:10217/219589