Efficiency Improvement Using Thickness-Chirped Barriers in Blue InGaN Multiple Quantum Wells Light Emitting Diodes

Wu Tian; Jun Zhang; Zhujuan Wang; Feng Wu; Yang Li; Shengchang Chen; Jin Xu; Jiangnan Dai; Yanyan Fang; Zhihao Wu; Changqing Chen

doi:10.1109/JPHOT.2013.2285714

IEEE Photonics Journal (Jan 2013)

Efficiency Improvement Using Thickness-Chirped Barriers in Blue InGaN Multiple Quantum Wells Light Emitting Diodes

Wu Tian,
Jun Zhang,
Zhujuan Wang,
Feng Wu,
Yang Li,
Shengchang Chen,
Jin Xu,
Jiangnan Dai,
Yanyan Fang,
Zhihao Wu,
Changqing Chen

Affiliations

Wu Tian: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology , Wuhan, China
Jun Zhang: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China
Zhujuan Wang: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China
Feng Wu: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China
Yang Li: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China
Shengchang Chen: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information , Huazhong University of Science and Technology, Wuhan, China
Jin Xu: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China
Jiangnan Dai: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China
Yanyan Fang: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information , Huazhong University of Science and Technology, Wuhan, China
Zhihao Wu: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, China
Changqing Chen: Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information , Huazhong University of Science and Technology, Wuhan, China

DOI: https://doi.org/10.1109/JPHOT.2013.2285714
Journal volume & issue: Vol. 5, no. 6
pp. 8200609 – 8200609

Abstract

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The advantages of blue InGaN light-emitting diodes (LEDs) with thickness-chirped barriers in the active region have been investigated by using the Crosslight APSYS programs. The results show that the output power of the proposed LED is increased 80% and the efficiency droop is decreased from 59% in conventional LED to 28% at the current of 250 mA. Based on the analysis of electrical and optical characteristics, these improvements are mainly attributed to the change of electrostatic field in the active region by using thickness-chirped barriers. In the even-numbered barriers, the fields are increased, which gets rid of more seriously bended valence band and results in decreased barrier heights for hole transport in the active region. Furthermore, the direction of electrostatic field in the last barrier is reversed to along the drift direction of holes, which not only can lead to upbended conduction band to rise the barrier height for electron escape but also can accelerate holes to increase the hole injection current. As a result, electrons blocking and holes injection are enhanced, and in turn, the performance of the proposed LED is improved.

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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