The 4.2K photoluminescence of bulk crystals, after neutron transmutation doping and electron irradiation, was investigated as function of the properties of the starting material, the irradiation dose, the thermal/fast neutron fluence ratio and the annealing conditions. The annealing behavior of the main photoluminescence bands in neutron transmutation doped GaAs was attributed to the formation and dissociation of non-radiative recombination centers which included residual acceptors (C, Si) and radiation-induced defects. A model for centers, including shallow acceptors of group-IV on As sites and interstitial transition metals, was considered. Complexes which consisted of neutral C atoms, metal impurities, shallow impurities and radiation-induced defects were identified in Ge after electron irradiation.

V.A.Bykovsky, N.I.Dolgikh, V.V.Emtsev, E.E.Haller, V.I.Hitko, L.M.Karpovich, V.F.Shoh, V.I.Utenko: Materials Science Forum, 1995, 196-201, 1413-8