scholarly journals Investigation on Light Extraction Behavior of Surface Plasmon-Coupled Deep-Ultraviolet LED in Different Emission Directions

Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 82
Author(s):  
Mei Ge ◽  
Yi Li ◽  
Youhua Zhu ◽  
Meiyu Wang
Keyword(s):  
Surface Plasmon ◽  
Three Dimensional ◽  
Strong Absorption ◽  
Light Extraction ◽  
Light Extraction Efficiency ◽  
Time Domain Simulation ◽  
Al Nanoparticles ◽  
Extraction Behavior ◽  
Deep Ultraviolet ◽  
Difference Time

The light extraction behavior of an AlGaN-based deep-ultraviolet LED covered with Al nanoparticles (NPs) is investigated by three-dimensional finite-difference time-domain simulation. For the transmission spectra of s- and p-polarizations in different emission directions, the position of maximum transmittance can be changed from (θ = 0°, λ = 273 nm) to (θ = 0°, λ = 286 nm) by increasing the diameter of Al NPs from 40 nm to 80 nm. In the direction that is greater than the critical angle, the transmittance of s-polarization is very small due to the strong absorption of Al NPs, while the transmittance spectrum of p-polarization can be observed obviously for the 80 nm Al NPs structure. For a ~284 nm AlGaN-based LED with surface plasmon (SP) coupling, although the luminous efficiency is significantly improved due to the improvement of the radiation recombination rate as compared with the conventional LED, the light extraction efficiency (LEE) is lower than 2.61% of the conventional LED without considering the lateral surface extraction and bottom reflection. The LEE is not greater than ~0.98% (~2.12%) for an SP coupling LED with 40 nm (80 nm) Al NPs. The lower LEE can be attributed to the strong absorption of Al NPs.

scholarly journals AlGaN-Delta-GaN Quantum Well for DUV LEDs

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 87
Author(s):  
Cheng Liu ◽  
Bryan Melanson ◽  
Jing Zhang
Keyword(s):  
Quantum Well ◽  
High Efficiency ◽  
Light Extraction Efficiency ◽  
Spontaneous Emission Rate ◽  
Light Emitting ◽  
Al Content ◽  
Recombination Efficiency ◽  
Promising Solution ◽  
Deep Ultraviolet ◽  
Difference Time

AlGaN-delta-GaN quantum well (QW) structures have been demonstrated to be good candidates for the realization of high-efficiency deep-ultraviolet (DUV) light-emitting diodes (LEDs). However, such heterostructures are still not fully understood. This study focuses on investigation of the optical properties and efficiency of the AlGaN-delta-GaN QW structures using self-consistent six-band k⸱p modelling and finite difference time domain (FDTD) simulations. Structures with different Al contents in the AlxGa1−xN sub-QW and AlyGa1−yN barrier regions are examined in detail. Results show that the emission wavelength (λ) can be engineered through manipulation of delta-GaN layer thickness, sub-QW Al content (x), and barrier Al content (y), while maintaining a large spontaneous emission rate corresponding to around 90% radiative recombination efficiency (ηRAD). In addition, due to the dominant transverse-electric (TE)-polarized emission from the AlGaN-delta-GaN QW structure, the light extraction efficiency (ηEXT) is greatly enhanced when compared to a conventional AlGaN QW. Combined with the large ηRAD, this leads to the significant enhancement of external quantum efficiency (ηEQE), indicating that AlGaN-delta-GaN structures could be a promising solution for high-efficiency DUV LEDs.

scholarly journals Plasmonic Coupling in Three-Dimensional Au Nanoparticle Assemblies Fabricated by Anodic Aluminum Oxide Templates

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Ahrum Sohn ◽  
Minji Gwon ◽  
Dukhyun Choi ◽  
Dong-Wook Kim
Keyword(s):  
Spectral Response ◽  
Three Dimensional ◽  
Au Nanoparticle ◽  
Time Domain Simulation ◽  
Aluminum Oxides ◽  
Plasmonic Coupling ◽  
Anodic Aluminum ◽  
Calculation Results ◽  
Anodic Aluminum Oxide Templates ◽  
Difference Time

We investigated optical properties of three-dimensional (3D) assemblies of Au nanoparticles (NPs), which were fabricated by dewetting of thin Au layers on anodic aluminum oxides (AAO). The NP assembly had hexagonal array of repeated multiparticle structures, which consisted of six trimers on the AAO surface and one large NP in the AAO pore (pore-NP). We performed finite-difference time-domain simulation to explain the optical response of the NP assemblies and compared the calculation results with experimental data. Such complementary studies clearly revealed how the plasmonic coupling between the constituent NPs influenced the spectral response of our NP assemblies. In particular, comparison of the assemblies with and without pore-NPs suggested that strong plasmonic coupling between trimers and pore-NP significantly affected the spectra and the field distribution of the NP assemblies. Plasmonic multi-NP assemblies could provide us new platforms to realize novel optoelectronic devices.

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