THERMOELECTRIC-POWER OF SOME COMPOSITIONS OF GETE-RICH (GETE)1-X(AGBITE2)X SOLID-SOLUTION

A method of preparation of single phase ingots of GeTe-rich solid solutions (x less-than-or-equal-to 0.20) in the system (GeTe)1-x(AgBiTe2)x is developed. The temperature dependence (77 to almost-equal-to 900 K) of thermoelectric power is measured. The curves for GeTe and GeTe-rich solid solutions are of similar shape. Using the conventional transport theory the lattice and electronic contributions to this effect are obtained. To explain the behavior of diffusion and phonon drag terms the metallic expressions for both are used. On the basis of band-edge models of GeTe and AgBiTe2 and the nonparabolic two-band Kane model of IV-VI compounds and separate values of the electronic parts of the thermoelectric power an information about the Fermi energy and the degree of degeneracy is received. A qualitative interpretation of the temperature dependence of S(e) is made.