title: Intrinsically core-shell plasmonic dielectric nanostructures with ultrahigh refractive index.
abstract: Topological insulators are a new class of quantum materials with metallic (edge) surface states and insulating bulk states. They demonstrate a variety of novel electronic and optical properties, which make them highly promising electronic, spintronic, and optoelectronic materials. We report on a novel conic plasmonic nanostructure that is made of bulk-insulating topological insulators and has an intrinsic core-shell formation. The insulating (dielectric) core of the nanocone displays an ultrahigh refractive index of up to 5.5 in the near-infrared frequency range. On the metallic shell, plasmonic response and strong backward light scattering were observed in the visible frequency range. Through integrating the nanocone arrays into a-Si thin film solar cells, up to 15% enhancement of light absorption was predicted in the ultraviolet and visible ranges. With these unique features, the intrinsically core-shell plasmonic nanostructure paves a new way for designing low-loss and high-performance visible to infrared optical devices.
authors.affiliation: Centre for Micro-Photonics and CUDOS (Centre for Ultrahigh bandwidth Devices for Optical Systems), Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
authors.forename: Zengji
authors.initials: Z
authors.lastname: Yue
authors.affiliation: Centre for Micro-Photonics and CUDOS (Centre for Ultrahigh bandwidth Devices for Optical Systems), Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
authors.forename: Boyuan
authors.initials: B
authors.lastname: Cai
authors.affiliation: School of Applied Sciences, RMIT University, Melbourne, Victoria 3001, Australia.
authors.forename: Lan
authors.identifier: 0000-0001-7124-2718
authors.initials: L
authors.lastname: Wang
authors.affiliation: Institute for Superconducting and Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500, Australia.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Centre for Micro-Photonics and CUDOS (Centre for Ultrahigh bandwidth Devices for Optical Systems), Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.; Artificial-Intelligence Nanophotonics Laboratory, School of Science, RMIT University, Melbourne, Victoria 3001, Australia.
authors.forename: Min
authors.initials: M
authors.lastname: Gu
mesh_terms: D004581:Electronics; D008027:Light; D049329:Nanostructures / Q000737:chemistry*; D012031:Refractometry; D012542:Scattering, Radiation; D012993:Solar Energy; D020349:Surface Plasmon Resonance
keywords: Topological insulator; core shell; dielectric; plasmonics; refractive Index