title: Particle-on-Film Gap Plasmons on Antireflective ZnO Nanocone Arrays for Molecular-Level Surface-Enhanced Raman Scattering Sensors.
abstract: When semiconducting nanostructures are combined with noble metals, the surface plasmons of the noble metals, in addition to the charge transfer interactions between the semiconductors and noble metals, can be utilized to provide strong surface plasmon effects. Here, we suggest a particle-film plasmonic system in conjunction with tapered ZnO nanowire arrays for ultrasensitive SERS chemical sensors. In this design, the gap plasmons between the metal nanoparticles and the metal films provide significantly improved surface-enhanced Raman spectroscopy (SERS) effects compared to those of interparticle surface plasmons. Furthermore, 3D tapered metal nanostructures with particle-film plasmonic systems enable efficient light trapping and waveguiding effects. To study the effects of various morphologies of ZnO nanostructures on the light trapping and thus the SERS enhancements, we compare the performance of three different ZnO morphologies: ZnO nanocones (NCs), nanonails (NNs), and nanorods (NRs). Finally, we demonstrate that our SERS chemical sensors enable a molecular level of detection capability of benzenethiol (100 zeptomole), rhodamine 6G (10 attomole), and adenine (10 attomole) molecules. This work presents a new design platform based on the 3D antireflective metal/semiconductor heterojunction nanostructures, which will play a critical role in the study of plasmonics and SERS chemical sensors.
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan Metropolitan City, 689-798, Republic of Korea.
authors.forename: Youngoh
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan Metropolitan City, 689-798, Republic of Korea.
authors.forename: Jiwon
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan Metropolitan City, 689-798, Republic of Korea.
authors.forename: Tae Kyung
authors.initials: TK
authors.lastname: Lee
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan Metropolitan City, 689-798, Republic of Korea.
authors.forename: Jonghwa
authors.initials: J
authors.lastname: Park
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan Metropolitan City, 689-798, Republic of Korea.
authors.forename: Minjung
authors.initials: M
authors.lastname: Ha
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan Metropolitan City, 689-798, Republic of Korea.
authors.forename: Sang Kyu
authors.initials: SK
authors.lastname: Kwak
authors.affiliation: Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan Metropolitan City, 689-798, Republic of Korea.
authors.forename: Hyunhyub
authors.initials: H
authors.lastname: Ko
keywords: ZnO nanocones; antireflective; gap plasmons; surface-enhanced Raman scattering; tapered waveguide