Designs of InGaN Micro-LED Structure for Improving Quantum Efficiency at Low Current Density
Shiqiang Lu1, Jinchai Li2,3, Kai Huang1,4
1Fujian Key Laboratory of Semiconductor Materials and Applications, CI Center for OSED, College of Physical Science and Technology, Xiamen University, Xiamen, 361005, People's Republic of China.
Nanoscale Research Letters
|June 3, 2021
Summary
Nitride micro-light-emitting-diodes (micro-LEDs) show a stronger quantum-confined Stark effect at low current densities. Optimizing carrier transport and removing the electron blocking layer (EBL) significantly enhance micro-LED efficiency and output power.
Area of Science:
- Solid State Physics
- Optoelectronics
- Materials Science
Background:
- Nitride micro-light-emitting-diodes (micro-LEDs) are crucial for advanced display technologies.
- Operating micro-LEDs at low current densities presents unique challenges related to efficiency and emission stability.
Purpose of the Study:
- To numerically investigate the operating behavior and physical mechanisms of nitride micro-LEDs at low current densities.
- To identify strategies for enhancing efficiency and achieving stable full-color emission in micro-LEDs.
- To optimize micro-LED structure design for improved performance.
Main Methods:
- Comprehensive numerical simulation of micro-LED performance.
- Analysis of polarization effects and quantum-confined Stark effect (QCSE).
- Investigation of carrier transport, carrier matching, and recombination processes (Auger, Shockley-Read-Hall).
Main Results:
- A severe quantum-confined Stark effect (QCSE) is observed at low current densities, impacting efficiency.
- Reducing quantum well numbers enhances carrier matching and radiative recombination.
- Removing the electron blocking layer (EBL) improves electron confinement and hole injection, boosting emission.
- Micro-LEDs exhibit high sensitivity to defect density at low current operation.
Conclusions:
- Optimizing epitaxial structures, including fewer quantum wells and removal of the EBL, is key for efficient low-current micro-LEDs.
- High doping and high hole concentration in p-GaN are beneficial for emissive displays.
- Understanding and mitigating defect sensitivity is critical for reliable micro-LED performance.
