Electroluminescent Diode Degradation Models

The general characteristics of gradual degradation of III-V compound electroluminescent diodes are reviewed. Seven possible degradation models are considered: high local temperatures, electric-field drift in the junction, electric-field drift in the bulk, optical flux effects, current drag, the extended-Longini mechanism, and the Gold-Weisberg mechanism. Only the last two mechanisms are found to be consistent with the data. At low current densities, the extended-Longini mechanism appears more reasonable, while at higher current densities the phonon-kick mechanism might be dominant. To further clarify the degradation characteristics, additional data is required at low temperatures and also at higher current densities.