Date of Project

11-30-2022

Document Type

Honors Thesis

School Name

College of Arts and Sciences

Department

Physics

Major Advisor

Dr. Muhammad Saleem

Second Advisor

Dr. Jen Miller

Abstract

Cathodoluminescence (CL) microscopy can be used to characterize the quantum optical behaviors of two-dimensional nanostructures. To investigate this behavior, we mounted flakes of tungsten disulfide (WS2), molybdenum disulfide (MoS2), and tungsten-sulfide-selenide Janus structures (WSSe) on a SiO2 substrate and analyzed these samples under both high vacuum and low H2O vacuum conditions using a scanning electron microscope. We then captured CL and secondary-electron images of the samples at multiple electron-beam energies and currents (5 keV to 30 keV, and 0.5 nA to 5 nA, respectively). We used a range of beam currents and energies to maximize image resolution while minimizing beam-induced sample damage. The images we secured were subjected to nonnegative matrix factorization and principal component analysis processing to identify and isolate areas of unique quantum optical behavior across various wavelengths. Artifacts in the CL images exposed flaws in this analysis methodology which prevented proper quantization of this behavior. Nevertheless, preliminary raw data showed evidence of non-uniform CL emission across flakes of WSSe and WS2.

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