The Effect of Sapphire Substrates on Omni-Directional Reflector Design for Flip-Chip Near-Ultraviolet Light-Emitting Diodes

Yonghui Zhang; Ji Zhang; Yuxin Zheng; Ce Sun; Kangkai Tian; Chunshang Chu; Zi-Hui Zhang; Jay Guoxu Liu; Wengang Bi

doi:10.1109/JPHOT.2018.2889319

IEEE Photonics Journal (Jan 2019)

The Effect of Sapphire Substrates on Omni-Directional Reflector Design for Flip-Chip Near-Ultraviolet Light-Emitting Diodes

Yonghui Zhang,
Ji Zhang,
Yuxin Zheng,
Ce Sun,
Kangkai Tian,
Chunshang Chu,
Zi-Hui Zhang,
Jay Guoxu Liu,
Wengang Bi

Affiliations

Yonghui Zhang: ORCiD; Institute of Micro-Nano Photoelectron and Electromagnetic Technology Innovation and the Key Laboratory of Electronic Materials and Devices of Tianjin, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin, China
Ji Zhang: Institute of Micro-Nano Photoelectron and Electromagnetic Technology Innovation and the Key Laboratory of Electronic Materials and Devices of Tianjin, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin, China
Yuxin Zheng: Institute of Micro-Nano Photoelectron and Electromagnetic Technology Innovation and the Key Laboratory of Electronic Materials and Devices of Tianjin, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin, China
Ce Sun: Institute of Micro-Nano Photoelectron and Electromagnetic Technology Innovation and the Key Laboratory of Electronic Materials and Devices of Tianjin, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin, China
Kangkai Tian: Institute of Micro-Nano Photoelectron and Electromagnetic Technology Innovation and the Key Laboratory of Electronic Materials and Devices of Tianjin, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin, China
Chunshang Chu: Institute of Micro-Nano Photoelectron and Electromagnetic Technology Innovation and the Key Laboratory of Electronic Materials and Devices of Tianjin, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin, China
Zi-Hui Zhang: ORCiD; Institute of Micro-Nano Photoelectron and Electromagnetic Technology Innovation and the Key Laboratory of Electronic Materials and Devices of Tianjin, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin, China
Jay Guoxu Liu: Beijing ShineOn Technology Ltd., Beijing, China
Wengang Bi: ORCiD; Institute of Micro-Nano Photoelectron and Electromagnetic Technology Innovation and the Key Laboratory of Electronic Materials and Devices of Tianjin, School of Electronics and Information Engineering, Hebei University of Technology, Tianjin, China

DOI: https://doi.org/10.1109/JPHOT.2018.2889319
Journal volume & issue: Vol. 11, no. 1
pp. 1 – 9

Abstract

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In this paper, we investigate the effect of omni-directional reflectors (ODRs) on the light extraction efficiency (LEE) for flip-chip near-ultraviolet light-emitting diodes (LEDs) on patterned (PSS) and flat sapphire substrate (FSS) using three-dimensional finite-difference time-domain method. Different design principles of ODR for the flip-chip LEDs on PSS and FSS are proposed to attain optimum LEE. For the flip-chip LED on FSS, the LEE curve is oscillatory with changing the thickness of the SiO2 layer as a result of the coherent interference in the ODR and the optical cavity tuning effect for light source. Therefore, the thickness of the p-GaN needs to satisfy even times of quarter wave and the thickness of SiO2 needs to be quarter wave. However, for the flip-chip LED on PSS, both the total internal reflection and the surface plasmon polariton resonance absorption play a major role leading to LEE increasing as the thickness of SiO2 layer increases. As a result, SiO2 layer with a thickness of over one wavelength is better, because the energy of evanescent wave decays to sufficiently negligible when it reaches the Al metal.

Published in IEEE Photonics Journal

ISSN: 1943-0655 (Online)
Publisher: IEEE
Country of publisher: United States
LCC subjects: Technology: Engineering (General). Civil engineering (General): Applied optics. Photonics; Science: Physics: Optics. Light
Website: http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=4563994

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