Gamma-Ray Irradiation Effects in Light-Emitting Diodes and Photodiodes for Fiber Optics

Permanent damage induced in AlGaAs LEDs, GaInAsP LEDs, Si PDs, and Ge PDs has been investigated for gamma-ray doses up to 108 rad(Si). Degradation in light output accompanied by a decrease in forward voltage and in increase in reverse current are induced above 107 rad(Si) for both AlGaAs and GaInAsP LEDs. Device recovery can be produced by applying a large forward current. Sensitivity remains constant up to 108 rad(Si) for both Si and Ge PDs. The dark current increment after irradiation is three orders of magnitude higher for Ge PDs than for Si PDs. Contribution of the DLTS-detected traps to the dark current is negligible.