Enhancement of the power factor of Pb_1–xSn_xTe (0.00 ≥ x ≥ 0.08) alloys

Abstract

Thermoelectric properties of Pb_1–x Sn _x Te (0.00 ≥ x ≥ 0.08) alloys synthesized by melting-quenching-annealing method have been investigated. The sample structure and phases have been investigated by Raman spectroscopy and X-ray diffraction, while the morphology and stoichiometry have been studied by SEM and EDX. The nanomaterial exists in a single phase and has a face-centred cubic (fcc) lattice of rock-salt type in the whole range of x values in Pb_1–x Sn _x Te alloys. The effect of tin substitution on the lattice vibration and chemical bonding nature in the lead telluride has been investigated by Raman spectroscopy at room temperature. The Seebeck coefficient and electrical resistivity have been measured in the temperature range of 100–400 K. The electrical resistivity measurements reveal that the compounds have extrinsic to intrinsic conduction transition and the electrical temperature transition shifts to higher values with increasing the Sn content. For all studied compounds, the Seebeck coefficient is positive indicating predomination of positive charge carriers over the entire temperature range. The thermoelectric power factor was enhanced to 2.03 mWm⁻¹ K⁻² for the sample with 4% Sn content at room temperature.

Keywords:

• alloys
• electrical properties
• grain size
• Raman spectroscopy
• semiconductors
• thermoelectric power