2020 Virtual undergraduate Research symposium
Revealing Structure in Atom Probe Tomography
PROJECT NUMBER: 93
AUTHOR: Brendan Paver, Physics
MENTOR: Jeramy Zimmerman, Physics | MENTOR: Andrew Proudian, Physics
ABSTRACT
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Materials systems, such as Organic Light Emitting Diode (OLED) displays, rely on the morphology of the material to make them efficient and durable. Atom Probe Tomography (APT) characterizes the 3D nanoscale structure of a material allowing for improvements in the manufacturing and device lifetimes of these systems. In APT, individual ions are evaporated from a sharp tip and accelerated toward a 2D detector. This 2D information, along with the order of evaporation, is used to reconstruct the 3D structure. Through evaporation simulations, focusing on the relationship between initial and final radial positions of each ion, this research is developing reconstructive models with improved spatial fidelity. A multivariate regression shows two key factors: a radial projection of the hemispherical sample end-form captures the majority of the behavior (Coefficient: (9.50±0.01)*10^-1), and a projection of the local surface normal around the evaporated ion that accounts for surface abnormalities (Coefficient: (4.54±0.07)10^-2). Moving forward, blends of material will be examined to test effects of phase boundaries, which will provide a basis for improved reconstruction models and better understanding of the APT technique.
VISUAL PRESENTATION
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AUTHOR BIOGRAPHY
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Brendan is a Junior in the Engineering Physics program with an interest in quantum technologies graduating in the Fall of 2020. He is currently pursuing radial reconstruction models for the Atom Probe Tomography process with hopes to create more precise models and better understanding allowing for more efficient use of ATP in material analysis. He has analyzed and produced a model for the radial reconstruction of a homogeneous tip and his next step is to pursue a non-homogeneous composition. In the future, he would like to explore the possible applications of machine learning in this research and see the applications of ATP with quantum materials.
This looks like very competent work, but I frankly could not figure out precisely what you have accomplished. The paper expresses no motivation for the work. It is written as if between you and your adviser, rather than between you and a relatively uninformed reader. For example, I never understood what rstart, rstop, and d represented. What is the significance of plotting rstop vs. rstart? What is the little cylinder in the upper left? The upper right hints that you are calculating something about the cylinder evaporating until it is a hemisphere – I think. Finally, and this is perhaps a matter of taste, but I thought that the layout and the evaporating tip at the bottom were rather too cute, but, more importantly, they cost you valuable space and made it hard for the reader to figure out the organization of the poster – across first, or down first? Or clockwise or counterclockwise? Next time, try to present your work to someone who, say, knows what APT is but knows nothing about your project.