Estimation of the recombination coefficients in aged InGaN laser diodes

We studied light-current characteristics in InGaN laser diode subjected to aging process. We observed anomalous behavior consisting in apparent increase of bimolecular recombination constant B. We proposed that the existence of a carrier escape mechanism proportional to N2 can fully account for this paradox. We show that it is possible to observe cathodoluminescence contrast in the degraded laser diodes. This contrast has uniform character through all the area of device. Our laser diodes are also characterized by deep defect center lying 0.82 eV below the conduction band minimum although we don't have yet a direct evidence of the existence of this level with device degradation.