Light-output enhancement of GaN-based light-emitting diodes with three-dimensional backside reflectors patterned by...

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• GaN-based LEDs are crucial for lighting applications.
• Light-extraction efficiency (LEE) is a key performance metric for LEDs.
• Flat backside reflectors limit LEE by not efficiently redirecting light.

Purpose of the Study:

• To investigate the enhancement of LEE in GaN-based LEDs using a novel 3D backside reflector.
• To demonstrate the effectiveness of a microscale SiO2 cone array combined with a distributed Bragg reflector (DBR).

Main Methods:

• Numerical simulation using Monte Carlo ray tracing.
• Fabrication of a 3D reflector comprising a microscale SiO2 cone array and a 16-pair Ti3O5/SiO2 DBR.
• Experimental measurement of wall-plug efficiency enhancement.

Main Results:

• 3D reflectors significantly improve LEE compared to flat reflectors.
• LEE increases with backside reflector reflectivity.
• A 12.1% enhancement in wall-plug efficiency was experimentally measured for the 3D DBR design.
• Simulated LEE enhancement for the 3D reflector was 11.73%.

Conclusions:

• The proposed 3D backside reflector, utilizing a microscale SiO2 cone array and DBR, effectively enhances LEE in GaN-based LEDs.
• The 3D structure improves light redirection into the escape cone.
• This approach offers a viable method for boosting LED performance.