What Limits the Efficiency of High-Power InGaN/GaN Lasers?

Blue light emitting InGaN/GaN lasers currently exhibit less than 40% wall-plug efficiency, while infrared InGaAs/GaAs laser diodes exceed 70%. This paper explores the reasons behind the efficiency limitation by the numerical analysis of measured InGaN/GaN laser characteristics. The study reveals a strong increase of the threshold current due to self-heating. The influence of Auger recombination, electron leakage, free-carrier absorption, and series resistance changes with rising injection current.