Enhanced thermoelectric performance of InTe through Pb doping

Chalcogenide semiconductors continue to be of prime interest for designing novel efficient materials for energy-conversion applications. Among them, the narrow-band-gap p-type semiconductor InTe exhibits high thermoelectric performance that mostly stems from its poor ability to transport heat. Here, we show that its thermoelectric figure of merit can be further enhanced by finely tuning the hole concentration through Pb doping. X-ray diffraction and scanning electron microscopy performed on the polycrystalline series In1-xPbxTe confirm that Pb substitutes for In with an estimated solubility limit below 1%. Pb acts as a donor-like impurity, driving the degenerate behavior of pristine InTe towards semiconducting-like properties. The enhanced disorder caused by this substitution increases point-defect scattering of phonons, leading to reduced lattice thermal conductivity. The resulting increase in the power factor and decrease in the phonon transport to values as low as 0.22 W m(-1) K-1 above 700 K yields a peak ZT value of 1.05 at 780 K for x = 0.1% along the direction parallel to the pressing direction. According to a single parabolic band model, this sample exhibits a near-optimal thermoelectric performance.

Automated summary

Pb doping in InTe semiconductor enhances thermoelectric performance by reducing lattice thermal conductivity and increasing power factor, resulting in improved thermoelectric properties.