Semiconducting Ge-Se-Sb-Ag chalcogenides as prospective materials for thermoelectric applications

Chalcogenide as thermoelectric materials have shown a large power factor to yield a high figure of merit. In this work we report the study of Ag doped Ge20Se60Sb20−xAgx(0 ≤ x ≤ 20 at%) chalcogenide materials in thin film form for the thermoelectric behaviour in the temperature range 300-450 K. Thin films have been prepared from the bulk samples by thermal evaporation. Electrical characterization analysis has also been reported. The dc conductivity increases while the activation energy decreases with the increase in Ag concentration. The type of the conductivity has been found to be p-type throughout the entire investigative temperature range where the sign of the thermoelectric power is positive. The concentration of the free carriers has been determined from dc conductivity and thermoelectric power measurements. The activation energy obtained from the thermoelectric power decreases while the power factor, which is one of the important thermoelectric parameters, increases with increasing silver content.