Current Dependent Electroluminescence Decay and Degradation Behaviour in Green and Yellow LED's

The injection current dependent electroluminescence decay time of green and yellow emitting diodes produced by Zn diffusion into VPE-GaP:N, Te and VPE-GaAs0.11P0.89:N, Te, respectively, is compared with the photoluminescence decay time measured in the as-grown layers independence on the excitation intensity. As it is possible to distinguish in this way between the nonradiative recombination at point defect centres and at dislocations the influence of these two types of defects can be investigated. This is confirmed applying this method to LED's prepared by different dicing methods. The degradation behaviour of the samples investigated can be understood in terms of decreasing minority carrier lifetime only in the n-region of the LED caused by increasing dislocation density.