It is shown that the introduction of copper atoms into GaAs crystals c
ontaining antistructure defects EL2 (isolated arsenic atoms on gallium
sites As-Ga) leads to a practically complete disappearance of the EL2
-induced luminescence bands peaked at 0.63 and 0.68 eV. This effect is
connected with the passivation of the EL2 defects (i.e. with the subs
tantial decrease in their concentration) because of their interaction
with copper atoms (they become bound by copper atoms) resulting in an
appearance of electrically inactive AsGaCuGa complexes.