Comparative study of aging-induced optical and electrical degradation and dynamic stability in GaN-on-sapphire and GaN-on-GaN micro-LEDs
Abstract
The aging behavior of GaN-based micro-light-emitting diodes (micro-LEDs) is strongly influenced by substrate material and device structures, yet systematic comparisons remain limited. In this work, we compared the aging-induced optical and electrical degradation of horizontal GaN-on-sapphire and GaN-on-GaN micro-LEDs under ultra-high current-density stress. The GaN-on-sapphire devices exhibit significant full width at half maximum (FWHM) broadening, peak wavelength shifts, reduced optical power, increased reverse leakage current, and elevated series resistance after aging, indicating enhanced defect-assisted recombination as well as increased carrier scattering and trapping. In contrast, GaN-on-GaN micro-LEDs show markedly improved stability in optical and electrical characteristics. Further frequency-dependent and voltage-dependent electrical analyses reveal substrate-dependent defect evolution during aging. Furthermore, step-current-density stress tests demonstrate superior dynamic voltage stability in GaN-on-GaN micro-LEDs, especially in vertical structures. These findings underscore the importance of GaN substrates and current transport geometry for improving micro-LED aging reliability.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (14)
Shan Huang
Zichun Li
The State Key Laboratory of Displays and Opto-Electronics, The Hong Kong University of Science and Technology 1 , Hong Kong,
Yibo Liu
Feng Feng
Department of Pharmaceutical Analysis
Jingyang Zhang
Key Laboratory for Green Chemical Technology of Ministry of Education, Collaborative Innovation Center of Chemical Science and Engineering, School of Chemical Engineering and Technology
Xinyi Liu
Ruixiang Zhu
The State Key Laboratory of Displays and Opto-Electronics, The Hong Kong University of Science and Technology 1 , Hong Kong,
Yinan Zhang
Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang Key Laboratory of Excited-State Energy Conversion and Energy Storage, State Key Laboratory of Silicon and Advanced Semiconductor Materials
Zhaoyong Liu
The State Key Laboratory of Displays and Opto-Electronics, The Hong Kong University of Science and Technology 1 , Hong Kong,
Fion Yeung
The State Key Laboratory of Displays and Opto-Electronics, The Hong Kong University of Science and Technology 1 , Hong Kong,
Manchun Tseng
The State Key Laboratory of Displays and Opto-Electronics, The Hong Kong University of Science and Technology 1 , Hong Kong,
Hoi Sing Kwok
The State Key Laboratory of Displays and Opto-Electronics, The Hong Kong University of Science and Technology 1 , Hong Kong,
Man Hoi Wong
SEMATECH 2 , Albany, New York 12203,
Zhaojun Liu
State Key Laboratory of Multiphase Flow in Power Engineering, Frontier Institute of Science and Technology