Atomic-scale structure of In1-xGaxSb thin films as-deposited and after ion irradiation

Extended x-ray absorption fine structure spectroscopy was used to investigate the neighborhood of In and Ga atoms in In1-xGaxSb thin films, deposited by magnetron sputtering and, subsequently, irradiated with 8 MeV Au+3 ions, with ion fluences ranging from 1 × 1013 cm−2 to 5 × 1014 cm−2. For as-deposited films, it was verified that the lattice mismatch in In1-xGaxSb is accommodated favorably through bond bending over bond stretching. This accommodation was modelled for all possible first nearest neighbor configurations based on experimentally determined structural parameters. Based on this, it was obtained that structural and electronic effects both contribute to the bandgap change in a similar way and neither local atomic arrangements nor charge redistribution can be neglected. Upon ion irradiation, this compound preserves its constant bond length value for the range of ion fluences used in this work.