HYDROGEN EFFECTS ON THE ELECTRICAL AND OPTICAL-PROPERTIES OF GAMMA-IRRADIATED N-TYPE GAAS EPILAYERS

The effects of gamma-irradiation on sulphur-doped VPE-grown GaAs epila yers exposed to a hydrogen plasma have been investigated by low-temper ature photoluminescence (PL), Hall effect and conductivity measurement s. It is shown that hydrogen incorporated into the samples from a plas ma prior to gamma-irradiation leads to significant changes in complex formation in n-type GaAs. PL measurements indicate that the presence o f hydrogen in n-type GaAs hinders the interaction of residual C-As acc epters with interstitial As atoms. Electrical measurements show a gamm a-induced decay of shallow donor-hydrogen complexes in hydrogenated n- type GaAs layers. In contrast to hydrogenated n-type Si, no increase o f radiation hardness with respect to electrical parameters of n-type G aAs subjected to hydrogenation and subsequent annealing at 390 degrees C has been observed.