scholarly journals Perspectives on UVC LED: Its Progress and Application

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 196
Author(s):  
Tsung-Chi Hsu ◽  
Yu-Tsai Teng ◽  
Yen-Wei Yeh ◽  
Xiaotong Fan ◽  
Kuo-Hsiung Chu ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
Flip Chip ◽  
Layer Structure ◽  
Light Emitting Diode ◽  
Internal Quantum Efficiency ◽  
Reverse Current ◽  
Light Extraction ◽  
Epitaxial Layers ◽  
High Electron ◽  
Recombination Rates

High-quality epitaxial layers are directly related to internal quantum efficiency. The methods used to design such epitaxial layers are reviewed in this article. The ultraviolet C (UVC) light-emitting diode (LED) epitaxial layer structure exhibits electron leakage; therefore, many research groups have proposed the design of blocking layers and carrier transportation to generate high electron–hole recombination rates. This also aids in increasing the internal quantum efficiency. The cap layer, p-GaN, exhibits high absorption in deep UV radiation; thus, a small thickness is usually chosen. Flip chip design is more popular for such devices in the UV band, and the main factors for consideration are light extraction and heat transportation. However, the choice of encapsulation materials is important, because unsuitable encapsulation materials will be degraded by ultraviolet light irradiation. A suitable package design can account for light extraction and heat transportation. Finally, an atomic layer deposition Al2O3 film has been proposed as a mesa passivation layer. It can provide a low reverse current leakage. Moreover, it can help increase the quantum efficiency, enhance the moisture resistance, and improve reliability. UVC LED applications can be used in sterilization, water purification, air purification, and medical and military fields.

scholarly journals Enhancement of quantum efficiency in InGaN quantum wells by using superlattice interlayers and pulsed growth

2016 ◽  
Vol 55 (4) ◽  
Author(s):  
Kazimieras Nomeika ◽  
Mantas Dmukauskas ◽  
Ramūnas Aleksiejūnas ◽  
Patrik Ščajev ◽  
Saulius Miasojedovas ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Quantum Efficiency ◽  
Light Emitting Diode ◽  
Internal Quantum Efficiency ◽  
Recombination Coefficient ◽  
Time Resolved ◽  
Mocvd Growth ◽  
Lower Strain ◽  
Type Contact ◽  
Ingan Quantum Wells

Enhancement of internal quantum efficiency (IQE) in InGaN quantum wells by insertion of a superlattice interlayer and applying the pulsed growth regime is investigated by a set of time-resolved optical techniques. A threefold IQE increase was achieved in the structure with the superlattice. It was ascribed to the net effect of decreased internal electrical field due to lower strain and altered carrier localization conditions. Pulsed MOCVD growth also resulted in twice higher IQE, presumably due to better control of defects in the structure. An LED (light emitting diode) structure with a top p-type contact GaN layer was manufactured by using both growth techniques with the peak IQE equal to that in the underlying quantum well structure. The linear recombination coefficient was found to gradually increase with excitation due to carrier delocalization, and the latter dependence was successfully used to fit the IQE droop.

Embeded photonic crystal at the interface of p-GaN and Ag reflector to improve light extraction of GaN-based flip-chip light-emitting diode

2014 ◽  
Vol 105 (25) ◽  
pp. 251103 ◽  
Author(s):  
Aigong Zhen ◽  
Ping Ma ◽  
Yonghui Zhang ◽  
Enqing Guo ◽  
Yingdong Tian ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Flip Chip ◽  
Light Emitting Diode ◽  
Light Extraction ◽  
Light Emitting ◽  
Ag Reflector

scholarly journals Sensitivity Analysis of GaN/AlGaN Quantum Dot Based Led

2021 ◽  
Author(s):  
Sumathi Kandasamy ◽  
Nagarajan K K ◽  
Srinivasan R
Keyword(s):  
Quantum Dot ◽  
Quantum Efficiency ◽  
Performance Metrics ◽  
Light Emitting Diode ◽  
Internal Quantum Efficiency ◽  
Optical Gain ◽  
Input Power ◽  
Geometrical Parameters ◽  
Significant Parameter ◽  
The Impact

Abstract The impact of various geometrical parameters and doping parameters on the performance of GaN/AlGaN quantum dot-based light-emitting diode using 3D numerical simulations have been studied in this work. The parameters are ranked based on their sensitivity coefficients. Four important performance metrics, (i) internal quantum efficiency, (ii) responsivity, (iii) optical gain, and (iv) input power are used for this study. The bottom radius of the quantum dot is found to be the most significant parameter with respect to the internal quantum efficiency and optical gain. Nanocolumn radius is the most significant parameter with respect to Responsivity and input power. The overall ranking suggests that the Nanocolumn radius is the most sensitive parameter.

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