Nuclear radiation displacement damage prediction in gallium arsenide through low temperature photoluminescence measurements

The intensity of the dominant peak in the photoluminescence (PL) spectrum of irradiated n and p-type GaAs has been measured for several energetic incident particles. The degradation of the PL intensity for all types of irradiations used in this work is quasi-linear with fluence in n-type GaAs. For p-type GaAs, the dependence is linear for electron irradiation and quasi-quadratic for neutron, proton and heavy ion irradiations. These results are compared with NIEL calculations for proton, electron and gamma irradiation. In n-type GaAs, the PL intensity was found to correlate well with NIEL for electron and proton irradiations. In comparing the gamma irradiation results with NIEL, the discrepancy is a factor of 30. This discrepancy is attributed to the weaker bound complexes formed by gamma irradiation compared to electron irradiation. In p-type GaAs, the PL intensity correlates well with NIEL for electron and proton irradiations if the definition of a degradation constant contains the linear dependence for the former and quadratic for the latter. The quadratic dependence is attributed to the formation of complexes. Annealing, whose partial effect is to dissociate complexes, confirms the consistency between NIEL and the data on proton and heavy ion irradiations. The weaker correlation between electron and neutron irradiation in the annealed samples is attributed to the U band defect, which is created by neutron irradiation but not by electron irradiation. The variety of possible complexes that form when GaAs is irradiated suggests that much caution should be taken when using electron or gamma irradiation to estimate damage due to heavier particles.