Reduced Surface Recombination in Extended-Perimeter LEDs toward Electroluminescent Cooling

Area of Science:

• Materials Science
• Semiconductor Physics
• Optoelectronics

Background:

• III-V semiconductor light-emitting diodes (LEDs) are key for electroluminescent cooling.
• Achieving high internal quantum efficiency (IQE) is essential for effective cooling.
• Nonradiative surface recombination at the device perimeter limits IQE in GaAs-based LEDs.

Purpose of the Study:

• To present an unconventional LED design to mitigate perimeter recombination losses.
• To enhance internal quantum efficiency in GaAs/InGaP double heterojunction LEDs.
• To improve the potential for electroluminescent cooling in semiconductor devices.

Main Methods:

• Fabrication of p-i-n GaAs/InGaP double heterojunction LEDs with varied sizes and perimeter extensions.
• Systematic variation of the distance between the current injection area and the device perimeter.
• Utilizing a Photon Dynamics model to estimate internal quantum efficiency changes.

Main Results:

• A 19% relative increase in external quantum efficiency (EQE) was achieved by extending the perimeter-to-contact distance.
• An estimated 5% relative increase in internal quantum efficiency (IQE) due to reduced perimeter recombination.
• The design successfully reduced perimeter recombination without compromising maximum current density.

Conclusions:

• Extending the perimeter-to-contact distance is an effective strategy to reduce nonradiative recombination.
• This method enhances IQE and EQE, advancing electroluminescent cooling in LEDs.
• The findings are applicable to other semiconductor devices limited by perimeter recombination.