The defects which were introduced into bulk semi-insulating material, by 6MeV proton bombardment at 300K, were investigated via electron paramagnetic resonance as detected via the magnetic circular dichroism of the optical absorption. Defects (EL20, EL2+) were introduced by the bombardment, with a total introduction rate of 100/cm. The radiation-induced EL2 defects could not be completely bleached. They had properties which were similar to those of the EL2 defects which were found in molecular beam epitaxial material at low temperatures.

Generation of EL2 defects by 6MeV proton-irradiation of semi-insulating GaAs S.A.Goodman, F.K.Koschnick, C.Weber, J.M.Spaeth, F.D.Auret: Solid State Communications, 1999, 110[11], 593-8