Power-Dependent Optical Characterization of the InGaN/GaN-Based Micro-Light-Emitting-Diode (LED) in High Spatial
Haifeng Yang1,2, Yufeng Li1,2, Jiawei Wang1,2
1Shaanxi Provincial Key Laboratory of Photonics & Information Technology, Xi'an Jiaotong University, Xi'an 710049, China.
Nanomaterials (Basel, Switzerland)
|July 14, 2023
Summary
Micro-LED efficiency varies spatially due to excitation power. Sidewall performance shifts from lower to higher than the center, impacting device uniformity and highlighting ion residue effects.
Area of Science:
- Optoelectronics
- Materials Science
Background:
- Micro-light-emitting diodes (micro-LEDs) are crucial for advanced displays.
- Understanding optical non-uniformity is key to improving micro-LED performance.
Purpose of the Study:
- To investigate the spatial distribution of optical non-uniformity in micro-LEDs.
- To analyze the impact of excitation power density on micro-LED efficiency.
- To identify factors contributing to efficiency variations across the micro-LED chip.
Main Methods:
- Spatially resolved photoluminescence spectroscopy at sub-micrometer scale.
- Variable power density excitation levels.
- Analysis of external quantum efficiency (EQE) droop and spectral variations.
Main Results:
- Efficiency at the sidewall was 80% lower than the center under low excitation, but 50% higher under high excitation.
- EQE droop was significantly different between the center (86%) and sidewall (52%).
- A 2 µm band near the sidewall showed rapid changes in efficiency, linked to indium composition variations from ion residues.
Conclusions:
- Spatial location significantly affects micro-LED efficiency trends with varying excitation levels.
- Ion residues and subsequent indium composition changes on sidewalls impact charge carrier distribution and efficiency.
- Findings provide insights into efficiency disadvantages and non-uniformity in small-sized micro-LEDs.
