Ultra-Thin Transition Metal Nitrides for Tunable Nanophotonic Devices
(Room Room 104-C)
29 Apr 19
2:00 PM
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2:20 PM
As a result of recent developments in nanofabrication techniques, the dimensions of metallic building blocks of plasmonic devices continue to shrink down to nanometer range thicknesses. The strong spatial confinement in atomically thin films lead to quantum phenomena, making ultra-thin films an ideal material platform to study light-matter interactions at the nanoscale. Additionally, the optical and electronic properties of ultra-thin metallic films (< 10 nm) are expected to have a strong dependence on compositional and structural factors, as well as an increased sensitivity to external optical and electrical perturbations. Consequently, unlike their bulk counterparts, the optical responses of atomically thin plasmonic films can be engineered by precise control of their thickness, substrate induced strain, and the dielectric properties of the substrate and superstrate. This unique tailorability establishes ultra-thin plasmonic films as an attractive material for the design of tailorable and dynamically switchable metasurfaces. In our current study, we present the epitaxial growth of continuous ultra-thin films of titanium nitride (TiN) varying thicknesses down to 2 nm using DC reactive magnetron sputtering. The investigated ultrathin films remain highly metallic, with a carrier concentration on the order of 1022 cm-3 even in the thinnest film (2 nm). Additionally, we demonstrate that the optical response can be engineered by controlling the thickness, strain, and surrounding dielectric environment.