Materials Science and Sensing Applications of Surface Plasmon Resonance in Conducting Metal Oxides

by Rhodes, Crissy Lynette

Surface plasmon resonance spectroscopy was developed for the conducting metal oxide, indium tin oxide (ITO). This technique detects changes in the refractive index of a substrate produced by a monolayer or biomolecule binding. To determine if effective monolayer binding occurred, many characterization techniques were employed including reflectance FT-IR, XPS, and near edge X-ray fine structure absorption (NEAXFS) spectroscopy. The reflectance FT-IR experimental data revealed not only confirmation of monolayer formation but evidence for the existence of the plasma frequency (?p) as predicted by the Drude Free Electron Model. The XPS data was primarily used as corroborating deposition evidence and NEXAFS spectroscopy was vital in recognizing the order or disorder of a deposition monolayer. Fundamental studies with Indium tin oxide revealed a strong dependence of the excitation of surface plasmons upon preparation conditions, crystal orientation, and skin depth. Complementary theoretical studies allowed for separation of the different plasmonic contributions in the thin film.