How much room for BiGa antisites in GaAsBi?, G. Ciatto, P. Alippi, A. A. Bonapasta, T. Tiedje, Appl. Phys. Lett. 99, 141912 (2011)

We addressed the issue of bismuth heteroantisite defects (BiGa) in GaAs_1-xBi_x/GaAs epilayers by coupling x-ray absorption spectroscopy at the bismuth edge with density functional theory calculations of the defect structure. Calculations predict a large relaxation of the Bi-As interatomic distances when Bi atoms substitute Ga, however we found no experimental evidence of it. Quantitative analysis of the x-ray absorption spectra allows us to establish a maximum concentration limit for BiGa, which corresponds to about 5% of the total Bi atoms. BiGa do not account for the modifications in the spectra previously attributed to short range ordering.