title: Enhanced external quantum efficiency in GaN-based vertical-type light-emitting diodes by localized surface plasmons.
abstract: Enhancement of the external quantum efficiency of a GaN-based vertical-type light emitting diode (VLED) through the coupling of localized surface plasmon (LSP) resonance with the wave-guided mode light is studied. To achieve this experimentally, Ag nanoparticles (NPs), as the LSP resonant source, are drop-casted on the most top layer of waveguide channel, which is composed of hydrothermally synthesized ZnO nanorods capped on the top of GaN-based VLED. Enhanced light-output power and external quantum efficiency are observed, and the amount of enhancement remains steady with the increase of the injected currents. To understand the observations theoretically, the absorption spectra and the electric field distributions of the VLED with and without Ag NPs decorated on ZnO NRs are determined using the finite-difference time-domain (FDTD) method. The results prove that the observation of enhancement of the external quantum efficiency can be attributed to the creation of an extra escape channel for trapped light due to the coupling of the LSP with wave-guided mode light, by which the energy of wave-guided mode light can be transferred to the efficient light scattering center of the LSP.
authors.affiliation: Institute of Electro-Optical Science and Technology, National Taiwan Normal University, 88, Sec. 4, Ting-Chou Rd., Taipei, 116, Taiwan.
authors.forename: Yung-Chi
authors.initials: YC
authors.lastname: Yao
authors.affiliation: Institute of Electro-Optical Science and Technology, National Taiwan Normal University, 88, Sec. 4, Ting-Chou Rd., Taipei, 116, Taiwan.|Advanced Lighting Technology Department, Green Energy and Environment Research Laboratories, Industrial Technology Research Institute (ITRI), Hsinchu 310, Taiwan.
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Hwang
authors.affiliation: Institute of Photonic System, National Chiao Tung University, 301, Gaofa 3rd Road, Tainan, 711, Taiwan.
authors.forename: Zu-Po
authors.initials: ZP
authors.lastname: Yang
authors.affiliation: Institute of Electro-Optical Science and Technology, National Taiwan Normal University, 88, Sec. 4, Ting-Chou Rd., Taipei, 116, Taiwan.
authors.forename: Jing-Yu
authors.initials: JY
authors.lastname: Haung
authors.affiliation: Institute of Photonic System, National Chiao Tung University, 301, Gaofa 3rd Road, Tainan, 711, Taiwan.
authors.forename: Chia-Ching
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Institute of Electro-Optical Science and Technology, National Taiwan Normal University, 88, Sec. 4, Ting-Chou Rd., Taipei, 116, Taiwan.
authors.forename: Wei-Chen
authors.initials: WC
authors.lastname: Shen
authors.affiliation: Institute of Electro-Optical Science and Technology, National Taiwan Normal University, 88, Sec. 4, Ting-Chou Rd., Taipei, 116, Taiwan.
authors.forename: Chun-Yang
authors.initials: CY
authors.lastname: Chou
authors.affiliation: Advanced Lighting Technology Department, Green Energy and Environment Research Laboratories, Industrial Technology Research Institute (ITRI), Hsinchu 310, Taiwan.
authors.forename: Mei-Tan
authors.initials: MT
authors.lastname: Wang
authors.affiliation: Institute of Electronics Engineering, National Taiwan University, Taipei 106, Taiwan.|Daxin Materials Corporation, No. 15, Keyuan 1st Road, Central Taiwan Science Park, Taichung, 407, Taiwan.
authors.forename: Chun-Ying
authors.initials: CY
authors.lastname: Huang
authors.affiliation: Graduate Institute of Photonics, National Changhua University of Education, No.1, Jinde Rd., Changhua 500, Taiwan.
authors.forename: Ching-Yu
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Department of Electrical Engineering, Chang Gung University, 259, Wen-Hwa 1st Rd., Kwei-Shan Dist., Taoyuan, 33302, Taiwan.
authors.forename: Meng-Tsan
authors.initials: MT
authors.lastname: Tsai
authors.affiliation: Physics Department, Chung Yuan Christian University, 200, Chung-Pei Rd., Chung Li Dist., Taoyuan, 32023, Taiwan.
authors.forename: Tzu-Neng
authors.initials: TN
authors.lastname: Lin
authors.affiliation: Physics Department, Chung Yuan Christian University, 200, Chung-Pei Rd., Chung Li Dist., Taoyuan, 32023, Taiwan.
authors.forename: Ji-Lin
authors.initials: JL
authors.lastname: Shen
authors.affiliation: Institute of Electro-Optical Science and Technology, National Taiwan Normal University, 88, Sec. 4, Ting-Chou Rd., Taipei, 116, Taiwan.
authors.forename: Ya-Ju
authors.initials: YJ
authors.lastname: Lee