Perspectives on UVC LED: Its Progress and Application
Tsung-Chi Hsu,
Yu-Tsai Teng,
Yen-Wei Yeh,
Xiaotong Fan,
Kuo-Hsiung Chu,
Su-Hui Lin,
Kuo-Kuang Yeh,
Po-Tsung Lee,
Yue Lin,
Zhong Chen,
Tingzhu Wu,
Hao-Chung Kuo
Affiliations
Tsung-Chi Hsu
Department of Photonics & Graduate Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
Yu-Tsai Teng
Fujian Engineering Research Center for Solid-State Lighting, School of Electronic Science and Engineering, Xiamen University, Xiamen 361005, China
Yen-Wei Yeh
Department of Photonics & Graduate Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
Xiaotong Fan
Fujian Engineering Research Center for Solid-State Lighting, School of Electronic Science and Engineering, Xiamen University, Xiamen 361005, China
Kuo-Hsiung Chu
Department of Photonics & Graduate Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
Su-Hui Lin
Fujian Engineering Research Center for Solid-State Lighting, School of Electronic Science and Engineering, Xiamen University, Xiamen 361005, China
Kuo-Kuang Yeh
Picosun China Co. Ltd., Suzhou 215000, China
Po-Tsung Lee
Department of Photonics & Graduate Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
Yue Lin
Fujian Engineering Research Center for Solid-State Lighting, School of Electronic Science and Engineering, Xiamen University, Xiamen 361005, China
Zhong Chen
Fujian Engineering Research Center for Solid-State Lighting, School of Electronic Science and Engineering, Xiamen University, Xiamen 361005, China
Tingzhu Wu
Fujian Engineering Research Center for Solid-State Lighting, School of Electronic Science and Engineering, Xiamen University, Xiamen 361005, China
Hao-Chung Kuo
Department of Photonics & Graduate Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan
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.
