Efficiency droop in gallium indium nitride (GaInN)/gallium nitride (GaN) LEDs

The decrease in efficiency at high current densities, i.e. the efficiency droop, is introduced in the context of GaInN/GaN light-emitting diodes (LEDs). We begin with an overview of the ABC model for the recombination of carriers in GaInN/GaN LEDs. The weaknesses of this model are described, and the model is reformulated by including a carrier leakage term. Several explanations for droop are presented and analyzed, including their strengths and weaknesses. Particular emphasis is given to high-level injection and the associated drift-induced electron leakage out of the active region. Finally, several proposed solutions to overcome efficiency droop are presented.