Effect of proton bombardment on GaAs luminescence

The effect of 6.6 MeV proton bombardment and subsequent annealing on the luminescence of Zn, Te-doped p-type GaAs crystals is studied and analysed. It is shown that: a) the proton bombardment leads to an appearance of the extrinsic emission band peaked at hνm ∼ 1.26 eV and to a marked decrease in the intensity of the near intrinsic (peaked at hνm ∼ 1.5 eV) emission band; b) subsequent annealing of proton-bombarded crystals leads, firstly, to a disappearance of the 1.26 eV emission band, and, secondly, to the appearance and then to the disappearance of the extrinsic emission bands peaked at hνm near 1.39 and 1.18 eV, and also to a restoration of the original intensity of the near intrinsic emission band. The above pointed variations in the GaAs luminescence spectra show the effective formation of AsiZnGa, VAsZnGa, and VGaTeAs pairs (besides isolated gallium and arsenic vacancies) with relatively low thermal stability in proton-irradiated unannealed (annealed) p-type GaAs crystals. (author)