This study investigates carrier recombination dynamics in InGaN/GaN quantum wells using time-resolved techniques, including induced grating methods, time-resolved photoluminescence, and pump–probe spectroscopy. Diffusion and carrier lifetime dependency on excitation density is systematically analyzed for structures with varying indium compositions and barrier configurations. The results reveal that carrier lifetime decreases while diffusion coefficients increase with rising excitation density, indicating enhanced nonradiative recombination under high carrier concentrations. This behavior is more pronounced in samples with higher indium content, suggesting a strong influence of carrier localization. The experimental observations are interpreted using an extended ABC recombination model that incorporates carrier density–dependent recombination processes. The analysis demonstrates that defect-assisted recombination becomes dominant at high excitation levels, while Auger recombination remains negligible within the investigated carrier density range. Furthermore, pump–probe measurements confirm distinct recombination pathways associated with localized and delocalized carrier states. These findings provide important insights into the physical mechanisms governing carrier dynamics and performance droop in InGaN-based quantum well designs, offering guidance for the optimization of high-performance optoelectronic devices.
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