Galvanomagnetic and optical properties of narrow-gap Pbsub(1-x)Snsub (x)Te semiconductors. The influence of Gd and Bi doping

The effect of Gd and Bi additions on galvanomagnetic (Hall effect and electric conductivity) and optical (the coefficient of edge absorption) properties of Pbsub(1-x)Snsub(x)Te monocrystals (x=0.16-0.20) is investigated. The Gd addition is shown to effect the width of the Pbsub(1-x)Snsub(x)Te forbidden zone and it results in occurrence of addition states with ΔE=0.01 eV under the bottom of the conductivity zone. Gd and Bi additions are donors. Determined are solubility in the Pbsub(1-x)Snsub(x)Te monocrystals which has a retrograde nature and it equals 2.2x1021 cm-3 at T=638+-5 deg C, as well as diffusion coefficient. Gd diffusion is stated to be exercised by vacant nodes of metal components of solid solution. It is shown that in Gd and Bi alloying the value of the ratio of electrons and holes mobilities changes