The stability of Frenkel pairs and group V interstitials in electron-irradiated GaAs and GaP

BGa impurity atoms selectively trap mobile group V interstitials to form defects designated B(1) centres in both GaAs and GaP during 2 MeV electron irradiation at room temperature. The production of these centres has been measured in both n-type and p-type material by infrared absorption and compared with a model proposed by Pons and Bourgoin relating to radiation-enhanced diffusion of the interstitial atoms. The results imply, however, that the dissociation of Frenkel pairs produced on the group V sublattice as primary defects control the process. The Frenkel pairs are stable in n-type material but not in p-type or high-resistivity material.