Performance degradation mechanism of irradiated GaAlAs LED

The degradation in performance of the device on GaAlAs light-emitting diodes (LEDs) irradiated by 2 MeV electrons and 70 MeV protons is investigated taking into account the recovery behavior. The reverse current increases after irradiation and the capacitance decreases. The device performance degradation is proportional to the fluence. The fluence rate is also relevant for degradation in electron irradiation. Low fluence rate leads to larger degradation compared to those associated with high fluence rate resulting from heat impact in bulk. The radiation damage of proton is larger than irradiation damage of electron, which is caused by the difference in mass and the possibility of nuclear collision for the formation of lattice defects. After irradiation, the device performance recovers by thermal annealing. The recovery behavior resulting from thermal annealing implies that the increase of reverse current for electroirradiation is mainly due to damage of the surface region.