Very Low-Efficiency Droop in 293 nm AlGaN-Based Light-Emitting Diodes Featuring a Subtly Designed p-Type Layer

Mu-Jen Lai; Yi-Tsung Chang; Shu-Chang Wang; Shiang-Fu Huang; Rui-Sen Liu; Xiong Zhang; Lung-Chien Chen; Ray-Ming Lin

doi:10.3390/molecules27217596

Very Low-Efficiency Droop in 293 nm AlGaN-Based Light-Emitting Diodes Featuring a Subtly Designed p-Type Layer

Molecules. 2022 Nov 5;27(21):7596. doi: 10.3390/molecules27217596.

Authors

Mu-Jen Lai¹, Yi-Tsung Chang², Shu-Chang Wang³, Shiang-Fu Huang^{4

5}, Rui-Sen Liu⁶, Xiong Zhang⁷, Lung-Chien Chen⁸, Ray-Ming Lin^{4

9}

Affiliations

¹ Jiangxi Yuhongjin Material Technology Co., Ltd., Fuzhou 344100, China.
² Department of Physics, School of Science, Jimei University, Xiamen 361021, China.
³ Changshu Institute of Technology, College of Electronics and Information Engineering, Changshu 215500, China.
⁴ Department of Otolaryngology-Head and Neck Surgery, Chang Gung Memorial Hospital, Taoyuan 33302, Taiwan.
⁵ Department of Public Health, Chang Gung University, Taoyuan 33302, Taiwan.
⁶ Guangdong Institute of Semiconductor Micro-Nano Manufacturing Technology, Foshan 528200, China.
⁷ Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China.
⁸ Department of Electro-Optical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan.
⁹ Department of Electronic Engineering and Institute of Electronics Engineering, Chang Gung University, Taoyuan 33302, Taiwan.

Abstract

This paper reports an AlGaN-based ultraviolet-B light-emitting diode (UVB-LED) with a peak wavelength at 293 nm that was almost free of efficiency droop in the temperature range from 298 to 358 K. Its maximum external quantum efficiencies (EQEs), which were measured at a current density of 88.6 A cm^-2, when operated at 298, 318, and 338 K were 2.93, 2.84, and 2.76%, respectively; notably, however, the current droop (J-droop) in each of these cases was less than 1%. When the temperature was 358 K, the maximum EQE of 2.61% occurred at a current density of 63.3 A cm^-2, and the J-droop was 1.52%. We believe that the main mechanism responsible for overcoming the J-droop was the uniform distribution of the concentrations of injected electrons and holes within the multiple quantum wells. Through the subtle design of the p-type AlGaN layer, with the optimization of the composition and doping level, the hole injection efficiency was enhanced, and the Auger recombination mechanism was inhibited in an experimental setting.

Keywords: AlGaN; MOCVD; efficiency droop; external quantum efficiency; light-emitting diode.

MeSH terms

Aluminum Compounds
Gallium*
Semiconductors*

Substances

aluminum gallium nitride
Gallium
Aluminum Compounds

Grants and funding

Jimei University Research Project (contract no. Z91956/4412), National Natural Science Foundation of China (grant no. 62005026), Natural Science Foundation of Jiangsu Province (grant no. BK20191027), Suzhou Science and Technology Project (grant no. SZS2020313), Ministry of Science and Technology (MOST) of Taiwan (contract no. MOST 109-2221-E-182 -060), and Chang Gung Memorial Hospital (grant no. BMRP 591).