High‐Quality, Ultraconformal Aluminum‐Doped Zinc Oxide Nanoplasmonic and Hyperbolic Metamaterials. Issue 7 (30th December 2015)

• Record Type: Journal Article
• Authors: Riley, Conor T.; Smalley, Joseph S. T.; Post, Kirk W.; Basov, Dimitri N.; Fainman, Yeshaiahu; Wang, Deli; Liu, Zhaowei; Sirbuly, Donald J.
• Is Part Of: Small. Volume 12:Issue 7(2016)
• Page Start: 892
• Page End: 901
• Publication Date: 2015-12-30
• Subjects: aluminum doping, zinc oxide -- atomic layer deposition -- metamaterials -- negative refraction -- plasmonics; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201501797
• Languages: English
• ISSNs: 1613-6810

Abstract

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. Abstract : Atomic layer deposition (ALD) is used to create low‐loss aluminum‐doped zinc oxide with carrier concentrations high enough to show plasmonic activity at 1550 nm. The highly conformal nature of ALD is exploited to achieve highly tunable localized surface plasmon resonant cavities and high‐quality hyperbolic metamaterials that cannot currently be made by any other process.