Degradation in AlGaInN lasers

Degradation experiments for AlGaInN-based laser diodes were conducted for the purpose of constructing a possible model of the degradation mechanism. Lasers in this experiment were aged under 30 mW continuous-wave operation at 60 °C, and the lifetime was defined as the time at which the operating current increased by 20%. The lifetime was found to be dependent on the dislocation density of the basal ELO-GaN layer, with the degradation rate being almost proportional to the square root of aging time. A model of degradation in which degradation is governed by a diffusion process is proposed based on these results. Although the model describes the experimental findings well, further investigation is considered necessary before the degradation mechanism in AlGaInN lasers can be fully understood. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)