CADMIUM DIFFUSION STUDIES OF PBTE AND PB1-XSNXTE CRYSTALS

Hall-effect, conductivity and solubility measurements were carried out on Cd-diffused PbTe and Pb1-xSnxTe. Our results show that the Cd solubility in the crystals is independent of the tin mole fraction. The data, examined in view of both Cd solubility and the influence of Cd upon the transport properties at 4.2K, indicate that after the metal vacancy sites become fully compensated by the Cd atoms most of the Cd distributes uniformly as an electrically inactive impurity in the crystal lattice. Saturation in electron concentration, which was observed at high Cd solubilities, provided a measure of the excess ionized metal point-defect concentration generated in the crystals during the growth process. The product of the concentrations of the excess metal and excess Te native point defects of the as-grown Pb1-xSnxTe was found to be practically constant for tin mole fractions 0{precedes or equal to}x{precedes or equal to}0.25, indicating that the equilibrium point defect constant is independent of the tin content. © 1979 AIME.