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ACS Appl Mater Interfaces. 2016 Jan 27;8(3):1653-60. doi: 10.1021/acsami.5b08382. Epub 2016 Jan 15.

Effect of SiO2 Spacer-Layer Thickness on Localized Surface Plasmon-Enhanced ZnO Nanorod Array LEDs.

Author information

1
Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education, Northeast Normal University , Changchun 130024, China.
2
State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , Changchun 130033, China.
3
Department of Physics, Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong.

Abstract

Localized surface plasmon (LSP)-enhanced ultraviolet LEDs have been constructed via spin-coating Ag nanoparticles onto ZnO/SiO2 core/shell nanorod array/p-GaN heterostructures. Different from the previous reports where the dielectric spacer-layer thickness was determined only through photoluminescence (PL) characterization, the SiO2 shell thickness in this work is also optimized by actual electroluminescence (EL) measurements to maximize the enhancement. It is interesting to find that the enhancement ratios derived from PL and EL measurements demonstrate different thickness dependences on SiO2 shell: an optimal 3.5-fold PL enhancement was obtained at the SiO2 thickness of 16 nm, while an "abnormal" 7-fold EL enhancement was achieved at the thickness of 12 nm. Time-resolved spectroscopy studies, as well as theoretical estimations and numerical simulations, reveal that the higher-ratio EL enhancement stems from joint contributions, both internal-quantum-efficiency improvement induced by exciton-LSP coupling and light-extraction-efficiency improvement aroused by photon-LSP coupling.

KEYWORDS:

ZnO/SiO2 core/shell nanorod array; exciton-LSP coupling; localized surface plasmon; luminescence enhancement; photon-LSP coupling; ultraviolet LED

PMID:
26741886
DOI:
10.1021/acsami.5b08382

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