A lattice-location study was made of Sn in Ge. From emission channelling experiments, the exact lattice location of ion implanted 121Sn atoms was determined and the results were compared to the predictions of density-functional calculations. The majority of the Sn atoms were positioned on the substitutional site, as could be expected for an isovalent impurity, while a second significant fraction occupies the sixfold coordinated bond-centered site, which was stable up to at least 400C. Corroborated by ab initio calculations, this fraction of bond-centered Sn atoms was attributed to the Sn-vacancy defect complex in the split-vacancy configuration. Furthermore, it was possible to assign specific defect complex geometries to resonances from earlier Mössbauer spectroscopy studies of Sn in Ge.

Lattice Location Study of Ion Implanted Sn and Sn-Related Defects in Ge. S.Decoster, S.Cottenier, U.Wahl, J.G.Correia, A.Vantomme: Physical Review B, 2010, 81[15], 155204