The influences of AlGaN barrier epitaxy in multiple quantum wells on the optoelectrical properties of AlGaN-based deep ultra-violet light-emitting diodes

Tien-Yu Wang; Wei-Chih Lai; Qiao-Ju Xie; Shun-Hao Yang; Sheng-Po Chang; Cheng-Huang Kuo; Jinn-Kong Sheu

doi:10.1039/d2ra07368d

The influences of AlGaN barrier epitaxy in multiple quantum wells on the optoelectrical properties of AlGaN-based deep ultra-violet light-emitting diodes

RSC Adv. 2023 Feb 13;13(8):5437-5443. doi: 10.1039/d2ra07368d. eCollection 2023 Feb 6.

Authors

Tien-Yu Wang¹, Wei-Chih Lai^{1

2}, Qiao-Ju Xie¹, Shun-Hao Yang¹, Sheng-Po Chang^{1

2

3}, Cheng-Huang Kuo⁴, Jinn-Kong Sheu^{1

2}

Affiliations

¹ Department of Photonics, National Cheng Kung University Tainan 70101 Taiwan weilai@ncku.edu.tw.
² Advanced Optoelectronic Technology Center, Research Center for Energy Technology and Strategy, National Cheng Kung University Tainan 70101 Taiwan.
³ Institute of Microelectronics and Department of Electrical Engineering, National Cheng Kung University Tainan 70101 Taiwan.
⁴ Institute of Lighting and Energy Photonics, College of Photonics, National Yang Ming Chiao Tung University Tainan 71150 Taiwan.

Abstract

The growth conditions of the AlGaN barrier in AlGaN/AlGaN deep ultra-violet (DUV) multiple quantum wells (MQWs) have crucial influences on the light output power of DUV light-emitting diodes (LEDs). The reduction of the AlGaN barrier growth rate improved the qualities of AlGaN/AlGaN MQWs, such as surface roughness and defects. The light output power enhancement could reach 83% when the AlGaN barrier growth rate was reduced from 900 nm h^-1 to 200 nm h^-1. In addition to the light output power enhancement, lowering the AlGaN barrier growth rate altered the far-field emission patterns of the DUV LEDs and increased the degree of polarization in the DUV LEDs. The enhanced transverse electric polarized emission indicates that the strain in AlGaN/AlGaN MQWs was modified by lowering the AlGaN barrier growth rate.