Charge State of Indium and Point Defects in Indium-Doped Lead Telluride Crystals

Experimental data on the lattice parameter, thermoelectric power, and microhardness of PbTe〈In〉 crystals and the conversion fromp- to n-type with increasing indium content can be interpreted under the assumption that the indium in PbTe〈In〉 has variable valence: 2In2+ ↔ In+ + In3+. A crystal-quasi-chemical model is proposed for defect formation in PbTe〈In〉: the incorporation of In+ into octahedral interstices and In3+ into tetrahedral interstices of the close packing of Te atoms, accompanied by In2Te3 precipitation.