A Review on Experimental Measurements for Understanding Efficiency Droop in InGaN-Based Light-Emitting Diodes

Lai Wang; Jie Jin; Chenziyi Mi; Zhibiao Hao; Yi Luo; Changzheng Sun; Yanjun Han; Bing Xiong; Jian Wang; Hongtao Li

doi:10.3390/ma10111233

A Review on Experimental Measurements for Understanding Efficiency Droop in InGaN-Based Light-Emitting Diodes

Materials (Basel). 2017 Oct 26;10(11):1233. doi: 10.3390/ma10111233.

Authors

Lai Wang¹, Jie Jin², Chenziyi Mi³, Zhibiao Hao⁴, Yi Luo⁵, Changzheng Sun⁶, Yanjun Han⁷, Bing Xiong⁸, Jian Wang⁹, Hongtao Li¹⁰

Affiliations

¹ Department of Electronic Engineering, Tsinghua University, Beijing 100084, China. wanglai@tsinghua.edu.cn.
² Department of Electronic Engineering, Tsinghua University, Beijing 100084, China. Jin-J15@mails.tsinghua.edu.cn.
³ Department of Electronic Engineering, Tsinghua University, Beijing 100084, China. mczy15@mails.tsinghua.edu.cn.
⁴ Department of Electronic Engineering, Tsinghua University, Beijing 100084, China. zbhao@tsinghua.edu.cn.
⁵ Department of Electronic Engineering, Tsinghua University, Beijing 100084, China. luoy@tsinghua.edu.cn.
⁶ Department of Electronic Engineering, Tsinghua University, Beijing 100084, China. czsun@tsinghua.edu.cn.
⁷ Department of Electronic Engineering, Tsinghua University, Beijing 100084, China. yjhan@tsinghua.edu.cn.
⁸ Department of Electronic Engineering, Tsinghua University, Beijing 100084, China. bxiong@tsinghua.edu.cn.
⁹ Department of Electronic Engineering, Tsinghua University, Beijing 100084, China. wangjian@tsinghua.edu.cn.
¹⁰ Department of Electronic Engineering, Tsinghua University, Beijing 100084, China. lihongtao@tsinghua.edu.cn.

Abstract

Efficiency droop in GaN-based light emitting diodes (LEDs) under high injection current density perplexes the development of high-power solid-state lighting. Although the relevant study has lasted for about 10 years, its mechanism is still not thoroughly clear, and consequently its solution is also unsatisfactory up to now. Some emerging applications, e.g., high-speed visible light communication, requiring LED working under extremely high current density, makes the influence of efficiency droop become more serious. This paper reviews the experimental measurements on LED to explain the origins of droop in recent years, especially some new results reported after 2013. Particularly, the carrier lifetime of LED is analyzed intensively and its effects on LED droop behaviors are uncovered. Finally, possible solutions to overcome LED droop are discussed.

Keywords: GaN; InGaN; carrier lifetime; efficiency droop; light-emitting diodes (LEDs); multiple quantum wells (MQWs).

Publication types

Review