Plasmonic Gallium Nanoparticles -- Attributes and Applications

Expanding the role of plasmonics in tomorrow's technology requires a broader knowledge base from which to develop such applications today. Several limitations to the current plasmonics field limit progress to incremental advances within a narrow set of materials and techniques rather than developing non-traditional metals and flexible growth and characterization methods. The work described herein will provide an introduction to the burgeoning field of spectroscopic ellipsometry for plasmonic characterization; in particular, the power of its real-time monitoring capabilities and flexibility will be demonstrated. More importantly, a novel plasmonic metal, gallium, is investigated in detail. Critical characteristics of gallium for an array of applications include its tunability over a wide spectral range, phase stability across a wide temperature range, plasmon stability even after air exposure, and an ultra high vacuum evaporation growth process enabling simple, alloyed nanostructure development. Deeper scientific investigation of the underlying ripening mechanisms driving gallium nanoparticle formation and in concert with in situ alloying paves the way for future work contributing to the development of advanced nanostructured alloys. Finally, this work demonstrates the first example of gallium nanoparticle-enhanced Raman spectroscopy - an area craving materials innovation. While the specific application of gallium for SERS detection is interesting, the far-reaching implication lies in the demonstrated potential for plasmonic gallium nanoparticles' ultimate use in a wider variety of applications enhanced by nanoscale materials.