Defect Centers in GaAs1−xPx Electroluminescent Diodes Due to High-Energy Electron Irradiation

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Abstract
Defect centers have been generated in GaAs1−xPx electroluminescent diodes by 1‐MeV electron irradiation. Junction capacitance and thermally stimulated current measurements on the irradiated diodes indicate two distinct types of centers. The first, an acceptor center in concentrations of 1−5×1017 cm−3, is found to be independent of GaAs1−xPx alloy composition, and is thought to be primarily responsible for an efficiency degradation previously described for irradiated GaAs1−xPx diodes. The second is a trapping center which is located 0.20–0.35 eV from either band edge, and whose concentration is shown to increase with alloy composition from 1×1015 cm−3 at x=0 to 4×1016 cm−3 at x=0.5. The two types of defects are each found to anneal from GaAs1−xPx at temperatures less than about 550°C. Furthermore, the annealing characteristics of the irradiated diodes establish a definite correlation between the generation and removal of the defect centers and the degradation and recovery of junction electroluminescent efficiencies.