Comparative analysis of efficiency limitations in GaN-based blue laser diodes

Nobel laureate Shuji Nakamura predicted in 2014 that GaN-based laser diodes are the future of solid state lighting. However, blue GaN-lasers still exhibit less than 40% power conversion efficiency, while GaN-based blue light-emitting diodes reach up to 84% This paper investigates non-thermal reasons behind this difference by comparative numerical device simulation. Fundamental material properties such as poor hole conductivity and high internal absorption are shown to make GaN-lasers inherently less efficient than GaAs-lasers.