  Carrier lifetime measurements reveal that, contrary to common expectations,
the high-current non-radiative recombination (droop) in III-Nitride light
emitters is comprised of two contributions which scale with the cube of the
carrier density: an intrinsic recombination --most likely standard Auger
scattering-- and an extrinsic recombination which is proportional to the
density of point defects. This second droop mechanism, which hasn't previously
been observed, is likely caused by an impurity-assisted Auger process. Further,
it is shown that longer-wavelength emitters suffer from higher point defect
recombinations, in turn causing an increase in the extrinsic droop process. It
is proposed that this effect leads to the green gap, and that point defect
reduction is a strategy to both vanquish the green gap and more generally
improve quantum efficiency at high current.
