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Detailed Program
Paper Number : LD-O01
Time Frame : 11:35~11:47
Presentation Date : Thurse day, 27, November
Session Name : LED and Display Materials
Session Chair 1# : In-Hwan Lee
Session Chair 2# : Motoaki Iwaya
Optical properties of Ag@SiO2 nanoparticles embedded nanopillar LED structures
Kang-Bin Bae
Chonbuk National University
Recent years have seen a growing interest in studying the effects of optical interaction between localized surface plasmons (LSPs) and GaN. The unique optical properties of LSPs have been studied for applications in sensing, imaging, surface enhanced spectroscopy, solar cells, and light-emitting diodes (LEDs). It has been demonstrated that LSPs coupling can also be utilized to enhance the light output of InGaN/GaN multi-quantum well (MQW) LED structure. The LSPs extend its distribution of near field electromagnetic field into the dielectric side for several tens of nanometers. At shorter distances of below 10 nm the Forster resonant energy transfer mechanism based on dipole–dipole interaction is operative. For the LSP enhancement to be efficient, the nanoparticles (NPs) layer should be placed in close proximity to the active MQW region of the device, generally no further than 40-60 nm. But, for very short distances from light-emitting layers, the light emission is generally quenched due to quantum mechanical tunneling effects.[1] In conventional LEDs, the emission efficiency depends on the optical extraction efficiency and internal quantum efficiency. Nanopillar LEDs can effectively increase the optical extraction efficiency, but not necessarily internal quantum efficiency (IQE). In order to try to improve the latter we have synthesized Ag@SiO2 core/shell structures using wet-chemical route and applied them to nanopillar LED structures. Nanopillar LED structures created by top-down method have some etching damage, as a result internal quantum efficiency decreases. To avoid this drawback, nanopillar LED using the bottom-up method have been prepared by molecular beam epitaxy. Ag@SiO2 NPs were deposited on this InGaN/GaN nanopillar LED structure.
In this study, photoluminescence behavior of nanopillar LED structures embedded with Ag@SiO2 NPs and the effect of surface plasmons on InGaN/GaN nanopillar LED with Ag@SiO2 NPs were investigated.


References:
[1] L.W. Jang, D.W Jeon, M. Kim, J.W. Jeon, A.Y. Polyakov, J.W. Ju, S.J. Lee, J.H. Baek, J.K. Yang and I.H. LEE, Adv. Funct. Mater. 22 (2012) 2728
Acknowledgements : This research was supported by National Research Foundation of Korea(NRF) funded by Ministry of Science, ICT & Future Planning (2013R1A2A2A07067688, 2010-0019626).