Determining the position of antimony impurity atoms in PbS by Sb-119(Sn-119m) emission Mossbauer spectroscopy

Emission Mossbauer spectroscopy based on the isotope Sb-119(Sn-119m) is use d to show that the location of antimony impurity atoms in the PbS lattice d epends on the conductivity type of the material: in n-type samples the anti mony is localized primarily on the anion sublattice, while in p-type materi al it is primarily on the cation sublattice. It is noteworthy that when the Sn-119m center appears in the anion PbS sublattice (i.e., as an antisite d efect) after radioactive conversion of Sb-119, its charge state does not de pend on the position of the Fermi level. When the Sb-119-center is in the c ation sublattice of PbS, it acts like an electrically active substitutional impurity: in n-type samples the spectrum corresponds to the neutral state of a donor center (Sn-119m(2+)), while in p-type material it corresponds to the doubly ionized state of this center (Sn-119m(4+)). (C) 1999 American I nstitute of Physics. [S1063-7826(99)00408-1].