Effects on the seebeck co-efficient and electrical properties of Tl10-x ATe6 (A= Pb & Sn) in chalcogenide system

Abstract

The different elements are doping in the tellurium telluride to determine the different properties like electrical and thermal properties of nanoparticles. The chalcogenide nanoparticles can be characteristics by the doping of the different metals which are like the holes. We present the effects of Pb and Sn doping on the electrical and thermoelectric properties of Tellurium Telluride Tl10-xPbxTe6 and Tl10-xSnxTe6(x=1.00, 1.25, 1.50, 1.75, 2.00) respectively, which were prepared by solid state reactions in an evacuated sealed silica tubes. Structurally, all these compounds were found to be phase pure as confirmed by the x-rays diffractometery (XRD) and energy dispersive X-ray spectroscopy (EDS) analysis. The thermo-power or Seebeck co-efficient (S) was measured for all these compounds which show that S increases with increasing temperature from 295 to 550 K. The Seebeck coefficient is positive for the whole temperature range, showing p-type semiconductor characteristics. Similarly, the electrical conductivity (σ) and the power factors have also complex behavior with Pb and Sn concentrations. The power factor (PF=S 2 σ) observed for Tl10-xPbxTe6 and Tl10-xSnxTe6 compounds are increases with increase in the whole temperature range (290 K-550 K) studied here. Telluride’s are narrow band-gap semiconductors, with all elements in common oxidation states, according to (Tl + ) 9 (Pb 3+ )(Te 2- )6 and (Tl + )9(Sn 3+ )(Te 2- )6. Phases range were investigated and determined with different concentration of Pb and Sn with consequents effects on electrical and thermal properties.