Study of mechanisms responsible for the efficiency degradation of the III-nitrides light emitting diodes

The results for external quantum efficiency degradation of two types of light emitting diodes based on III-nitrides: blue and ultraviolet ones are presented. Existing mechanisms proposed for the degradation are considered briefly. Applying several techniques for studying the light emitting diodes at various stages of the aging test gives the possibility to reveal a new mechanism of defects formations with a help of multi-phonon recombination of carriers in an extended defects system and in local regions of random alloy fluctuations. These techniques include analysis of current voltage characteristics evolution at V