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We consider the influence of preliminary irradiation by 60Co gamma quanta on emission power decrease during the operating time of IR‐LEDs based upon AlGaAs double heterostructures. Irradiation was realized in passive power mode of the LEDs prior to aging. Aging under long operating time conditions was simulated by a step‐stress approach. We have determined that the emissive power decrease of LED during operating time has two stages. On the first stage, decrease of LED emissive power is due to rearrangement of original defect structure. On the second stage, emissive power goes down as the result of inducing new structural defects. We have shown identical multistage mechanisms of emissive power drop are observed during both operating time and influence of ionizing radiation. We have established that preliminary irradiation has increased reliability and operating time of LEDs. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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There are two distinctive regions can be identified (low (LC) and high currents (HC)) of a watt-ampere (W-I) characteristic of initial LEDs based upon GaP with 590 nm wavelength. The established patterns differ in the exponent. At the same time, the LC region corresponds to an increase in the efficiency of conversion of operating current into light radiation, and the HC region is a slow decline with an increase in the operating current. As a result of irradiation with gamma-quanta in the passive power mode, the change in the shape ofW-Icharacteristic is established, which can be characterized by an increase in the threshold current separating the LC and HC regions with an increase in the irradiation dose. The change in the emissive power of the LEDs and the shift of the threshold current occurs in two stages: in the first stage, the emissive power decreases due to radiation-stimulated rearrangement of the initial defect structure. At the same time, with an increase in the radiation dose, a partial recovery of the emissive power is observed against the background of its overall decrease. At the end of the first stage, the dependence of the damage coefficient on the operating current density in measurements of theW-Icharacteristics is manifested explicitly. The second stage of reducing the emissive power due to the introduction of radiation defects. In this case, the damage coefficient does not depend on the working current density, and the observed differences are due to the fact that by the end of the first stage its contribution to the overall reduction in emissive power is inversely proportional to the working current density. The established patterns can be used at the stage of designing the LEDs to substantiate the choice of the optimal value of the operating current density and to predict the resistance to irradiation with gamma rays.