Local structure around Fe in the diluted magnetic semiconductors Ga1-xFexAs studied by x-ray absorption fine structure - art. no. 195209

Extended x-ray absorption fine structure and near-edge x-ray absorption fin e structure techniques are employed to investigate the local structure and valency about Fe atoms in the diluted magnetic alloy semiconductor system G a1-xFexAs prepared by molecular-beam epitaxy under various conditions. This experiment is aimed at elucidating possible correlations between the micro structures in these diluted magnetic semiconductors and some physical prope rties. Our x-ray results offer direct evidence of Fe substitution for Ga si tes in GaAs prepared at relatively low substrate temperatures, wherein the Ga1-xFexAs compound is mainly paramagnetic. However, the Fe impurity atoms could form small Fe clusters and/or Fe-As complexes when the samples are gr own at high temperatures.