Exploring the Application of Plasmonic Group IV Transition Metal Nitrides via Surface Modification Strategies

Abstract

The interest in plasmonic transition metal nitrides (TMNs) has expanded recently due to the chemical and thermal stability of their bulk counterparts. While their popularity has grown, the chemical properties of nano-sized TMNs have remained unexplored. As chemical properties such as stability dictate the feasibility of TMNs, this doctoral work first analyzes pH and oxidative stability of these nanomaterials. Amongst investigation via UV-Vis spectroscopy, TiN experienced complete oxidation in 60 days, while ZrN and HfN remained relatively stable. However, all three TMNs showed stable pH ranges of 2-3, observed via zeta potential measurements. Dispersibility studies of TMN nanoparticles showed water as the only functional solvent. The focus of this thesis is stability enhancement of group 4 TMNs (TiN, ZrN and HfN) using surface modification techniques. For surface functionalization studies, multiple silanes (APTES, dimethyldichlorosilane, mPEG-silane) were used as coupling agents due to their reactivity with hydroxy-terminated oxide shells on TMN surfaces.