Quantum Efficiency of III-Nitride Emitters: Evidence for Defect-Assisted Nonradiative Recombination and its Effect on the Green Gap

$I\phantom{\rule{0}{0ex}}I\phantom{\rule{0}{0ex}}I$-N emitters have enabled the technological revolution of LED lighting, but some applications remain hindered by two phenomena, of debated origin, that degrade quantum efficiency at high power in long-wavelength LEDs (the ``green gap''). In this study of carrier dynamics, the authors discover that two effects are intertwined, and correlated with defect density. Beyond the commonly known effect, defective samples suffer from an additional form of nonradiative recombination at high current, and this trend is exacerbated at long wavelengths. These findings provide guidance for developing more efficient LEDs, at all powers and wavelengths.