Dissertation Defense: Andrew Stoner
Candidate: Andrew Stoner
Major: Chemistry
Advisor: Jong-In Hahm, Ph.D.
Title: Investigating the Enhancement Abilities of Individual 1D ZnO NRs and their Heterojunction Variations Using Confocal Raman Spectroscopy
ZnO nanorods (NRs) have been researched to be applied as a chemical and biological sensor due to their unique chemical and physical properties. These unique properties originate from its high shape anisotropy and waveguiding abilities. These properties have been shown to enhance fluorescence signals from surface coupled fluorophores. This enhancement was shown to be the most intense at the NRs ends. Presently, all analysis using ZnO NRs to enhance Raman signals have been conducted using bulk material of ZnO. In this dissertation, confocal Raman spectroscopy and z-depth mapping was utilized to understand how 1D ZnO NRs can enhance Raman signals of model polymer analytes. Additionally, the ability of individual ZnO NRs to effectively couple and guide fluorescence emission when uniaxial mechanical strain was applied along the long axis of the NR was examined. The presence of uniaxial mechanical strain on the ZnO NR was confirmed utilizing confocal Raman spectroscopy. Finally, I studied the ability of combining an individual ZnO NR with an individual Ag NR to create a semiconductor-metal heterojunction to see if these individual heterojunctions could further enhance Raman scattering emission. I ascertained the degree of enhancement on Raman scattering intensity from individual spatially resolved ZnO NR / Ag NR heterojunction substrates. These studies will prove to be valuable in the development of highly sensitive single ZnO NR containing Raman probes.