title: High-Quality, Ultraconformal Aluminum-Doped Zinc Oxide Nanoplasmonic and Hyperbolic Metamaterials.
abstract: Aluminum-doped zinc oxide (AZO) is a tunable low-loss plasmonic material capable of supporting dopant concentrations high enough to operate at telecommunication wavelengths. Due to its ultrahigh conformality and compatibility with semiconductor processing, atomic layer deposition (ALD) is a powerful tool for many plasmonic applications. However, despite many attempts, high-quality AZO with a plasma frequency below 1550 nm has not yet been realized by ALD. Here a simple procedure is devised to tune the optical constants of AZO and enable plasmonic activity at 1550 nm with low loss. The highly conformal nature of ALD is also exploited to coat silicon nanopillars to create localized surface plasmon resonances that are tunable by adjusting the aluminum concentration, thermal conditions, and the use of a ZnO buffer layer. The high-quality AZO is then used to make a layered AZO/ZnO structure that displays negative refraction in the telecommunication wavelength region due to hyperbolic dispersion. Finally, a novel synthetic scheme is demonstrated to create AZO embedded nanowires in ZnO, which also exhibits hyperbolic dispersion.
authors.affiliation: Department of NanoEngineering, University of California, San Diego, La Jolla, CA, 92093, USA.
authors.forename: Conor T
authors.initials: CT
authors.lastname: Riley
authors.affiliation: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, 92093, USA.
authors.forename: Joseph S T
authors.initials: JS
authors.lastname: Smalley
authors.affiliation: Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA.
authors.forename: Kirk W
authors.initials: KW
authors.lastname: Post
authors.affiliation: Department of Physics, University of California, San Diego, La Jolla, CA, 92093, USA.
authors.forename: Dimitri N
authors.initials: DN
authors.lastname: Basov
authors.affiliation: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, 92093, USA.|Materials Science and Engineering, University of California, San Diego, La Jolla, CA, 92093, USA.
authors.forename: Yeshaiahu
authors.initials: Y
authors.lastname: Fainman
authors.affiliation: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, 92093, USA.|Materials Science and Engineering, University of California, San Diego, La Jolla, CA, 92093, USA.
authors.forename: Deli
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA, 92093, USA.|Materials Science and Engineering, University of California, San Diego, La Jolla, CA, 92093, USA.
authors.forename: Zhaowei
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of NanoEngineering, University of California, San Diego, La Jolla, CA, 92093, USA.|Materials Science and Engineering, University of California, San Diego, La Jolla, CA, 92093, USA.
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Sirbuly
keywords: aluminum doping, zinc oxide; atomic layer deposition; metamaterials; negative refraction; plasmonics