An intrinsic, material-level explanation for the efficiency droop of GaN light-emitting diodes: as carrier concentration rises under high injection, the non-equilibrium excess electrons and holes develop mismatched momentum distributions, suppressing direct radiative recombination. Teaches how GaN's own band structure and momentum conservation, rather than only Auger, polarization, or defect effects, limit internal quantum efficiency - evidenced by droop in excitonic photoluminescence but droop-free phonon-assisted recombination.
This paper proposes an intrinsic, material-level cause for the long-standing 'efficiency droop' of GaN light-emitting diodes - the sharp fall in internal quantum efficiency at high injection. Working…