| In the past decade, great leaps have been made in developing metamaterials --- man-made materials tailored to display behaviors not found in nature. This research looks away from conventional metals, such as Au and Ag, and towards Al which has been shown to have lower losses in the optical region and a higher plasma frequency, which is related to carrier concentration. Paired with nano layers of SiO2 or ZnO, the overall structure can create hyperbolic dispersion. This dispersion occurs when the parallel and perpendicular permittivites have opposite signs leading to enhanced stimulated emission and decreased rates.;Using spectroscopic ellipsometry, the deposition of Al with both SiO 2 and ZnO was investigated. This work utilizes the Transfer-Matrix formalism with the effective medium approximation to predict ellipsometry data, and the Levenberg-Marquardt algorithm is used to fit it. These techniques allow for conclusions to be made about material properties.;Results show that at room temperature, RF sputtering of Al with SiO 2 does not deposit pure Al. Instead, a layer Al3O2 was found to best-fit the data. Modeling efforts show that the Al content increased by 13% within the Al3O2 layer when the temperature during deposition increased. The presence of Al3O2 inhibits hyperbolic effects since it is a dielectric, so new techniques will be considered to fabricate Al/SiO2 in further research.;When Al is combined with ZnO using atomic layer deposition (ALD), it exists as a Al-doped ZnO layer, also called AZO. An initial investigation for the ellipsometry data used the Drude model and found that a nanolayered structure, made using ALD, had an order-of-magnitude lower losses than silver and other AZO/ZnO growing methods. Future work will look at developing a more complex model for AZO and experimental means of verifying these findings. |
