Unravelling concurring degradation mechanisms in InGaAlP light-emitting diode structures by optical overstress experiments under reverse bias

摘要

We examine the influence of an applied reverse bias on the optically induced and measured photoluminescence degradation characteristics of an InGaAlP light-emitting diode (LED) structure. We show that a reverse bias applied simultaneously to laser excitation of the sample has a strong impact on the observable photoluminescence degradation properties of the structure investigated via intense laser excitation. With the help of this approach, it is possible to control the carrier density and the internal electric field of the diode independently. By doing this, a distinction of several usually interfering photoluminescence degradation mechanisms from each other is achievable. Further, a comparison of the experimental data with simulated data delivers some indication on the local origin of the defect evolution processes within the light-emitting diode structure.