Microstructural and thermoelectric properties of PbTe single crystals as grown by Czochralski method

Abstract

• PbTe single crystal was successfully grew by a rapid synthetic Czochralski technique onto cubic rock salt (NaCl) structure. • Semiconductor behavior within Te-rich has been induced the both Seebeck coefficient ( S ) values for p-type and n-type. • Thermoelectric power factor value of p-type is more than n-type around two orders of magnitude. A single crystal of Lead Telluride (PbTe) has been grown by Czochralski technique. The microstructure of PbTe alloy as grown showed the cubic rock salt (NaCl) structure as confirmed by the XRD and TEM results. The composition of Pb:Te ratio of around 1:1.1 was indicated the Te-rich. The effect of temperature has induced the transport of charges after intrinsic excitation of PbTe to be changed the Seebeck coefficient ( S ) values of positive (p-type) at low-temperature range (<550 K) to the negative (n-type) at high-temperature range (>550 K). The maximum thermoelectric power factor ( PF ) of p-type is 1.91 mW m −1 K −2 at room temperature (RT) and n-type is 0.063 mW m −1 K −2 at 673 K to be concluded the value of p-type more than n-type around two orders of magnitude. The maximum dimensionless figure of merit ( ZT ) value is around 0.41 at 300 K.