Thermal and efficiency droop in InGaN/GaN light-emitting diodes: decoupling multiphysics effects using...

Area of Science:

• Semiconductor physics
• Optoelectronics
• Materials science

Background:

• Thermal and efficiency droop are significant challenges in InGaN/GaN light-emitting diodes (LEDs).
• Multiphysics processes like recombination, carrier transport, and heating contribute to droop.
• A clear method to isolate these factors under electrical injection is needed.

Purpose of the Study:

• To decouple and quantify recombination, injection, transport, and thermal effects in InGaN/GaN LEDs.
• To understand the root causes of efficiency and thermal droop.
• To establish a robust methodology for analyzing III-nitride LED performance.

Main Methods:

• Utilized a comprehensive rate equation approach.
• Employed a temperature-dependent pulsed-radio frequency (RF) measurement technique.
• Investigated electrically injected single-quantum-well InGaN/GaN LEDs.

Main Results:

• Efficiency droop at high current densities is attributed to non-radiative recombination (Auger-like) and radiative rate saturation.
• Thermal droop at elevated temperatures is caused by carrier redistribution towards non-radiative processes.
• The study successfully decoupled inherent recombination dynamics.

Conclusions:

• The developed methodology provides unambiguous access to quantum well recombination dynamics.
• This approach is valuable for diagnosing efficiency limitations in III-nitride LEDs.
• Understanding these processes is crucial for improving LED performance and reliability.