It was shown that Fe-Al and Fe-B pairs underwent excitation-induced dissociation under illumination at about 150K, where the thermally activated motion of Fe atoms was almost impossible. The Fe-doping was achieved by annealing specimens, which had been pre-doped with Al or B, in Fe vapor at 1050C; followed by quenching. At first, Fe-acceptor pairs were generated by annealing the specimens at 80C. The illumination effect upon the concentrations of the first- and second-nearest neighbor pairs of Fe-acceptors was then studied at various temperatures. Illumination with light at about 150K reduced the concentration of the first-nearest neighbor pair while increasing that of the second-nearest neighbor pair. The activation energy for Fe atom motion from the first-nearest to the second-nearest neighbor of an Al atom was estimated to be equal to 0.11eV under illumination.

S.Sakauchi, M.Suezawa, K.Sumino: Materials Science Forum, 1995, 196-201, 1345-50