Radiation Damage and Hardening Effects on Compensated GaAs Light-Emitting Diodes

Closely compensated GaAs light-emitting diodes utilizing Zn-Si and Si-Si impurity combinations have been used to study the effects of both gamma and neutron irradiation on the radiative light generating mechanism as well as on the carrier lifetime and injection mechanism in these diodes. The following results have been noted: 1) the light-generating mechanism appears to be affected more strongly by 60Co irradiation than by neutron irradiation; 2) the shallow-lying acceptor radiative center (Zn) appears to be more susceptible to 60Co irradiation than the deeper-lying center (Si); 3) neutron irradiation appears to introduce non-radiative centers which primarily affect the lifetime and injection mechanism. A means of radiation hardening GaAs light-emitting diodes by isovalent substitutional alloying of phosphorus is reported. A minimum reduction in quantum efficiency on neutron irradiation occurs for the alloy composition GaAs.70 P.30.