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Efficiency droop in zincblende InGaN/GaN quantum wells
D Dyer1, S A Church1, R Ahumada-Lazo1,2
1Department of Physics and Astronomy & Photon Science Institute, University of Manchester, Manchester, M13 9PL, UK. david.binks@manchester.ac.uk.
Nanoscale
|July 9, 2024
Summary
Zincblende Indium Gallium Nitride/Gallium Nitride quantum wells show potential for high-brightness LEDs by delaying efficiency droop. Further material improvements are needed to fully realize their potential.
Area of Science:
- Materials Science
- Solid State Physics
- Optoelectronics
Background:
- Efficiency droop in c-plane wurtzite Indium Gallium Nitride/Gallium Nitride (InGaN/GaN) quantum wells limits high-brightness light-emitting diode (LED) applications.
- Strong polarization fields in wurtzite InGaN/GaN exacerbate droop, hindering performance.
Purpose of the Study:
- Investigate zincblende InGaN/GaN quantum wells as an alternative to mitigate droop.
- Understand the fundamental mechanisms of emission and efficiency in these materials.
Main Methods:
- Excitation-dependent photoluminescence and photoreflectance spectroscopy were employed.
- Polarization-resolved measurements characterized emission origins.
- Photomodulated reflection determined the onset of efficiency droop.
Main Results:
- Emission primarily originates from similar microstructures within the quantum well layers.
- Non-radiative recombination significantly impacts emission efficiency, even at low temperatures.
- Efficiency droop onset in zincblende InGaN/GaN occurred at a carrier density of 1.2 × 10^20 cm^-3, an order of magnitude higher than wurtzite.
Conclusions:
- Zincblende InGaN/GaN quantum wells demonstrate potential for delaying efficiency droop in GaN-based LEDs due to higher carrier density droop onset and shorter carrier lifetimes.
- Improving material quality by preventing microstructure formation and elucidating the role of non-radiative centers are crucial for realizing the full potential of zincblende InGaN/GaN.
