The influence of irradiation by &agr; particles and subsequent isochronal annealing onn-GaAs doped with silicon, was investigated. Photoluminescence (PL) studies revealed the formation of an induced radiation center at 1.486 eV. In addition to the PL investigation we also employed capacitance–voltage(C–V)measurements and deep level transient spectroscopy (DLTS). TheC–Vmeasurements indicate a slight reduction inn-type carriers in treated samples and the DLTS spectra showed a number of commonly observed deep levels in irradiated samples (not annealed), which disappear after annealing. Based on the experimental evidence we propose that the 1.486 eV band is due to a donor-acceptor-pair transition. Alternative mechanisms are also discussed. ©1997 American Institute of Physics.