Proton damage effects on light emitting diodes

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Abstract
We have studied the effects of 16‐MeV proton irradiation on the performance of a variety of light emitting diodes (LED’s) emitting between 820 and 1300 nm. Total light output and current were measured at room temperature as a function of forward bias prior to and following a sequence of room temperature 16‐MeV proton irradiations. Our results indicate that the relative amount of proton‐induced degradation from one LED type to another is similar to that observed for neutron and gamma irradiations. More specifically, the most sensitive device is the amphoterically Si‐doped GaAs LED which is characterized by a long preirradiation minority carrier lifetime. The most resistant LEDs are the high radiance GaAlAs (820 nm) and InGaAsP (1300 nm) LEDs. As in the case of Si devices, the degradation rate per irradiating particle fluence is significantly greater for proton irradiation of these LEDs than it is for neutron exposure. Neutron damage data presented herein indicate that the ratio of proton‐to‐neutron degradation rates can be as high as 100. Lifetime‐damage constant products for constant current operation are calculated for each LED type and vary from 1.5×10−13 cm2/p for the InGaAsP LED to 1.1×10−10 cm2/p for the amphoterically Si‐doped GaAs LED.