The linear absorption of bulk material which had been bombarded with Au+ ions or protons was measured at a wide range of wavelengths below the gap. Good agreement was found between absorption data and calculated elementary defect concentrations. Defect clustering was detected in the heavy-ion case. Pump-probe experiments were used to measure time-resolved absorption variations for weakly irradiated samples under intense illumination. Much shorter carrier recombination times were estimated in the heavy-ion case.

Sub-Gap Optical Absorption and Recombination Center Efficiency in Bulk GaAs Irradiated by Light or Heavy Ions J.Mangeney, J.Lopez, N.Stelmakh, J.M.Lourtioz, J.L.Oudar, H.Bernas: Applied Physics Letters, 2000, 76[1], 40-2