Solid State Transformations and Electrophysical Properties of GeTe-Rich Solid Solutions in the GeTe-Ag2Te-Bi2Te3 System

Abstract

Equilibrium polycrystalline samples of GeTe‐rich (GeTe)1−x[(Ag2Te)1‐y(Bi2Te3)y]x (y = 0.4667, 0.5000, and 0.5333) SS are prepared. On the base of different experimental investigations the T‐x projection of the phase equilibrium diagram of SS with y = 0.4667 is drawn. The GeTe‐rich SS keep the crystal structure of GeTe. The phase transition temperature Tc decreases with increasing amount of the ternary compound and reaches 300 K at x of about 0.23. From a comparision of the power coefficient S2σ of SS with different y at 300 K it is found that a deviation in stoichiometry of the ternary compound towards Ag2Te (y = 0.4667) or Bi2Te3 (y = 0.5333) influences unfavorably the thermoelectric parame‐ters.