scholarly journals Nanostructural Effect of ZnO on Light Extraction Efficiency of Near-Ultraviolet Light-Emitting Diodes

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Young Jae Park ◽  
Hyounsuk Song ◽  
Kang Bok Ko ◽  
Beo Deul Ryu ◽  
Tran Viet Cuong ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Light Extraction Efficiency ◽  
Zno Nanostructures ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Output Efficiency ◽  
Ultraviolet Light Emitting Diodes

The effect of ZnO nanostructures on the light output power of 375 nm near-ultraviolet light-emitting diodes (NUV-LEDs) was investigated by comparing one-dimensional (1D) nanorods (NR-ZnO) with two-dimensional (2D) nanosheets (NS-ZnO). ZnO nanostructures were grown on a planar indium tin oxide (ITO) by solution based method at low temperature of 90°C without degradation of the forward voltage. At an injection current of 100 mA, the light output efficiency of NUV-LED with NR-ZnO was enhanced by around 30% compared to the conventional NUV-LEDs without ZnO nanostructures. This improvement is due to the formation of a surface texturing, resulting in a larger escape cone and a multiple scattering for the photons in the NUV-LED, whereas the light output efficiency of NUV-LED with NS-ZnO was lower than that of the conventional NUV-LEDs due to the internal reflection and light absorption in the defective sites of NS-ZnO.

Internal quantum efficiency of highly-efficient InxGa1−xN-based near-ultraviolet light-emitting diodes

2003 ◽  
Vol 83 (24) ◽  
pp. 4906-4908 ◽  
Author(s):  
Satoshi Watanabe ◽  
Norihide Yamada ◽  
Masakazu Nagashima ◽  
Yusuke Ueki ◽  
Chiharu Sasaki ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Internal Quantum Efficiency ◽  
Light Emitting ◽  
Highly Efficient ◽  
Near Ultraviolet ◽  
Ultraviolet Light Emitting Diodes

scholarly journals Enhanced Radiative Recombination Rate by Local Potential Fluctuation in InGaN/AlGaN Near-Ultraviolet Light-Emitting Diodes

2019 ◽  
Vol 9 (5) ◽  
pp. 871 ◽  
Author(s):  
Abu Islam ◽  
Dong-Soo Shim ◽  
Jong-In Shim
Keyword(s):  
Potential Energy ◽  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Internal Quantum Efficiency ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Energy Fluctuation ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Ultraviolet Light Emitting Diodes

We investigate the differences in optoelectronic performances of InGaN/AlGaN multiple-quantum-well (MQW) near-ultraviolet light-emitting diodes by using samples with different indium compositions. Various macroscopic characterizations have been performed to show that the strain-induced piezoelectric field (FPZ), the crystal quality, and the internal quantum efficiency increase with the sample’s indium composition. This improved performance is owing to the carrier recombination at relatively defect-free indium-rich localized sites, caused by the local in-plane potential-energy fluctuation in MQWs. The potential-energy fluctuation in MQWs are considered to be originating from the combined effects of the inhomogeneous distribution of point defects, FPZ, and indium compositions.

scholarly journals Enhanced Optical Output of Near-Ultraviolet Light-Emitting Diodes by a Monolayer of Nanospheres

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Wei Wan ◽  
Zhanxu Chen ◽  
Yongzhu Chen ◽  
Gengyan Chen
Keyword(s):  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Low Cost ◽  
Incident Light ◽  
Light Extraction Efficiency ◽  
Light Emitting ◽  
Hexagonal Close Packed ◽  
Exit Surface ◽  
Near Ultraviolet ◽  
Optical Output

The optical output of near-ultraviolet (NUV) light-emitting diodes (LEDs) was improved by including a monolayer of hexagonal close-packed polystyrene (PS) nanospheres. PS nanospheres with different sizes were deposited on the indium tin oxide layer of the NUV LEDs. The electroluminescence results showed that the light extraction efficiency of the NUV LEDs was increased by the inclusion of PS nanospheres, and the maximum optical output enhancement was obtained when the size of the nanospheres was close to the light wavelength. The largest enhancement of the optical output of 1.27-fold was obtained at an injection current of 100 mA. The enhanced optical output was attributed to part of the incident light beyond the critical angle being extracted when the exit surface of the NUV LEDs had a PS nanosphere monolayer. This method may serve as a low-cost and effective approach to raise the efficiency of NUV LEDs.

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