Role of sintering temperature in modulating the charge transport of BiCuSeO thermoelectric system: correlations to the microstructure

The influence of sintering temperature on the thermoelectric (TE) transport of BiCuSeO is reported in the present work, with an aim to optimize the processing conditions for higher TE transport. BiCuSeO samples were synthesized at four different sintering temperatures, viz., 673 K, 773 K, 873 K, and 973 K. A non-degenerate type of conductivity is observed in all the samples at high temperatures, witnessing the thermal activation of the carriers. The Fermi level was positioned below the valence band maximum, thereby exhibiting a p-type degenerate transport in the entire range of temperature. It was observed that the variations of weighted mobility and power factor were found to have identical trends. The highest power factor was noticed at 554 K with a value of 129 μWm −1 K −2 for the sample sintered at 673 K.