DEFECTS IN SODIUM-DOPED LEAD AND TIN CHALOGENIDES - FORMATION, INTERACTION, AND INFLUENCE OF THE DEFECTS ON THE ELECTRONIC-SPECTRUM

Studies are made of a broad range of changes in the transport properti es of sodium-doped Pb1-xSnxSe (x=0.03-0.10) solid solutions associated with the presence of resonant impurity states which fix the location of the Fermi level. It is shown that only a small fraction of Sn atoms (less than 1.3 at.%) participate in the formation of the impurity ban d. A model is proposed for defect formation in the lead and tin chalco genides and for their interaction which depends on the type of chalcog enide, The properties of sodium-doped solid solutions of Pb(Sn)Te and Pb(Sn)Se are interpreted in terms of this model. (C) 1996 American Ins titute of Physics.