title: Enhanced waveguide-type ultraviolet electroluminescence from ZnO/MgZnO core/shell nanorod array light-emitting diodes via coupling with Ag nanoparticles localized surface plasmons.
abstract: Localized surface plasmon (LSP) enhanced waveguide-type ultraviolet light-emitting diodes (LEDs) were fabricated by sputtering Ag nanoparticles (Ag-NPs) onto ZnO/MgZnO core/shell nanorod array (CS-NRA)/p-GaN heterostructures. A ∼9-fold enhancement of ZnO ultraviolet electroluminescence (EL) was demonstrated by the Ag-NPs decorated LED compared with the device without Ag-NPs. Angle-dependent EL measurements, as well as finite-difference time-domain simulations of the EL intensity spatial distribution, confirmed the waveguide-type EL transmission mode along the NR's axial direction. The increased spontaneous emission rate observed in time-resolved spectroscopy suggested that the ZnO EL enhancement was attributed to LSP-exciton/polariton coupling. However, a direct coupling is very difficult to achieve between Ag-LSPs and electron-hole pairs in the active region due to their "remote" separation. Thereby, two possible models involving the dynamic process of interactions among excitons, photons, and LSPs, were established to understand the selective enhancement of ZnO EL.
authors.affiliation: 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. hyxu@nenu.edu.cn ycliu@nenu.edu.cn.
authors.forename: Cen
authors.initials: C
authors.lastname: Zhang
authors.forename: Claire Elizabeth
authors.initials: CE
authors.lastname: Marvinney
authors.forename: Hai Yang
authors.initials: HY
authors.lastname: Xu
authors.forename: Wei Zhen
authors.initials: WZ
authors.lastname: Liu
authors.forename: Chun Liang
authors.initials: CL
authors.lastname: Wang
authors.forename: Li Xia
authors.initials: LX
authors.lastname: Zhang
authors.forename: Jian Nong
authors.initials: JN
authors.lastname: Wang
authors.forename: Jian Gang
authors.initials: JG
authors.lastname: Ma
authors.forename: Yi Chun
authors.initials: YC
authors.lastname: Liu