Mid-infrared resonant cavity light emitting diodes operating at 4.5 µm

Area of Science:

• Optoelectronics
• Semiconductor Devices
• Infrared Technology

Background:

• Mid-infrared light emitting diodes (LEDs) are crucial for gas sensing.
• Traditional LEDs suffer from low intensity, broad spectral linewidth, and poor temperature stability.
• Resonant cavity enhancement offers a pathway to improve LED performance.

Purpose of the Study:

• To design and fabricate a mid-infrared resonant cavity light emitting diode (RCLED) operating at 4.5 µm.
• To evaluate the performance enhancements of the RCLED compared to a reference LED.
• To demonstrate the potential of the RCLED for gas detection applications.

Main Methods:

• Fabrication of a micro-cavity structure using molecular beam epitaxy (MBE).
• The cavity contains an AlInAs/InAsSb quantum well active region.
• Distributed Bragg reflector (DBR) mirrors made of AlAsSb/GaSb were used.

Main Results:

• The RCLED achieved a peak intensity 85x higher than a reference LED.
• Integrated output power was 13x higher, and spectral linewidth was 16x narrower.
• The RCLED demonstrated 7x superior temperature stability.

Conclusions:

• The developed RCLED exhibits significantly enhanced performance characteristics.
• Its high spectral brightness, narrow linewidth, and stability are suitable for N2O detection at 4.5 µm.
• The device can be adapted for detecting CO2 (4.2 µm) and CO (4.6 µm).