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

Abstract

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.

Effect of Aging on the Photoelectrical Properties of AlGaInP LEDs

“…It is to be noted that in [37] and [38], the minima of optical output were observed on the same 1-h scale as in our paper, which strongly implies that the above-described evolution of photoelectrical characteristics is also due to the defects that are related to recombination-enhanced processes of growth and annealing.…”

“…Recent investigation of the short-term photoluminescence degradation mechanisms in AlGaInP LED structures exposed to intense laser radiation [37], [38] proved that both the growth and annealing of nonradiative recombination defects in AlGaInP LEDs are due to recombination-enhanced processes [39], [40] rather than to current-driven ones. It is to be noted that in [37] and [38], the minima of optical output were observed on the same 1-h scale as in our paper, which strongly implies that the above-described evolution of photoelectrical characteristics is also due to the defects that are related to recombination-enhanced processes of growth and annealing.…”