The influence of nano structuring and combined doping (Ag and Sb) on the thermoelectric properties of PbTe thin films

Abstract

Nanocrystalline PbTe and Ag & Sb co-doped PbTe thin films are prepared using an integrated physical-chemical approach by evaporating chemically synthesized PbTe and Ag & Sb co-doped PbTe nanopowders on glass substrates. The X-Ray Diffractogram (XRD) reveals that all samples are NaCl-type structure and the structural parameters such as crystallite size D, dislocation density $\delta$, strain $\epsilon$, lattice constant, volume of the cell and number of crystallites are calculated and reported the results. The crystallite size of the films is around 24 nm. The absolute value of the Seebeck coefficient of nanocrystalline PbTe and Ag and Sb co-doped PbTe thin films is 1.069 mV/K and 0.569 mV/K respectively and the positive values indicate their p-type conductivity of the film. The values of Seebeck coefficient and power factor are higher than that of bulk which implies an enhancement in the thermoelectric properties with a reduction in the particle size and co doping.