Improvement of Near-Infrared Light-Emitting Diodes' Optical Efficiency Using a Broadband Distributed Bragg Reflector...

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Near-infrared light-emitting diodes (NIR-LEDs) are crucial for various applications.
• Improving the optical efficiency of NIR-LEDs is an ongoing research challenge.
• Distributed Bragg reflectors (DBRs) are key components for enhancing LED performance.

Purpose of the Study:

• To develop an advanced broadband distributed Bragg reflector (DBR) for 850 nm NIR-LEDs.
• To enhance the optical efficiency and output power of 850 nm NIR-LEDs.
• To investigate the effect of nanomaterial-based multiple structures and buffer layers on DBR performance.

Main Methods:

• Fabrication of a combined 850 nm centered broadband DBR using two DBRs centered at 800 nm and 900 nm.
• Incorporation of a reflective Aluminum Arsenide (AlAs) buffer layer to reduce overlapped reflection.
• Characterization of the combined DBR's optical properties and comparison with conventional DBRs.
• Integration of the DBR into 850 nm NIR-LED chips and measurement of output power.

Main Results:

• The combined DBR exhibited a wider peak band compared to conventional DBRs.
• The AlAs buffer layer significantly increased the peak band width by reducing overlapped reflection.
• NIR-LED chips with the combined DBR and AlAs buffer layer achieved an output power of 20.5 mW.
• This represents a >40% improvement over conventional 850 nm DBRs (14.5 mW).

Conclusions:

• The combined broadband DBR design effectively enhances optical efficiency in 850 nm NIR-LEDs.
• The strategic combination of DBR wavelengths and the AlAs buffer layer is crucial for maximizing the broadband effect.
• This advanced DBR technology offers a significant improvement for NIR-LED performance and potential applications.