PbTe based superlattice structures with high thermoelectric efficiency

We report on an enhanced thermoelectric figure of merit ${\mathrm{ZT=\sigma S}}^2\mathrm{T/\lambda }$ (where σ is electrical conductivity, $S$ is thermopower, $T$ is absolute temperature, and λ is thermal conductivity) for $\mathrm{PbTe}/{\mathrm{PbSe}}_{\text{0.20}}{\mathrm{Te}}_{\text{0.80}}$ superlattices (SLs) and PbTe doping SLs due to a reduction of the thermal conductivity λ parallel to the layer planes. Despite a small decrease of the power factors ${\mathrm{\sigma S}}^2$ due to a reduction of σ in these superlattices, the figure of merit is higher as compared to the corresponding bulk materials and reaches maximum values in the temperature range between 400 and 570 K.