Perspectives on UVC LED: Its Progress and Application

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 ha...

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Bibliographic Details
Published in:Photonics 2021-06, Vol.8 (6), p.196
Main Authors: Hsu, Tsung-Chi, Teng, Yu-Tsai, Yeh, Yen-Wei, Fan, Xiaotong, Chu, Kuo-Hsiung, Lin, Su-Hui, Yeh, Kuo-Kuang, Lee, Po-Tsung, Lin, Yue, Chen, Zhong, Wu, Tingzhu, Kuo, Hao-Chung
Format: Article
Language:English
Subjects:
Air purification
Aluminum oxide
atomic layer deposition
Atomic layer epitaxy
Current leakage
Design
disinfection
Efficiency
Encapsulation
Epitaxial layers
Irradiation
Lamps
Light emitting diodes
Light irradiation
Materials selection
Moisture resistance
Packaging design
Photodegradation
Quantum efficiency
Recombination
Semiconductors
Sterilization
Transportation
Ultraviolet radiation
UVC LED
Water purification
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Summary: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.
ISSN:2304-6732
2304-6732
DOI:10.3390/photonics8060196