Radiation Susceptibility of High Power (>200 mW) Spontaneous Infrared Emitters.

The effects of neutron and gamma irradiation on high-power (>200 mW) GaAs dome infrared emitters are reported. The threshold radiation levels for degradation of radiated power output, power efficiency, and external quantum efficiency are observed for neutron fluences of 1 x 10 to the 12th power n/sq. cm. (E > 10 keV) and for total gamma doses of 1 million rads (Si). These parameters decrease by three orders of magnitude at 2.2 x 10 to the 14th power n/sq. cm. for the neutron-irradiated device, and at 10 to the 8th power rads (Si) for the gamma-irradiated device. The reduction in power efficiency and external quantum efficiency with irradiation can be explained by the reduction in total minority carrier lifetime. The effect of radiation on the dome is negligible. The results of intensity-voltage and current-voltage measurements confirm that, even under the effects of nuclear irradiation, light is emitted in the diffusion region of the junction and that the charge flow is a diffusion process. (Author)