Origin of resistivity anomaly in p-type leads chalcogenide multiphase compounds

Sima Aminorroaya Yamini,David R G Mitchell,Shi Xue Dou,Zachary M Gibbs,G Jeffrey Snyder,Yanzhong Pei,Heng Wang

doi:10.1063/1.4913992

Abstract

The electrical resistivity curves for binary phase compounds of p-type lead chalcogenide (PbTe)(0.9−x)(PbSe)0.1(PbS)x, (x = 0.15, 0.2, 0.25), which contain PbS-rich secondary phases, show different behaviour on heating and cooling between 500-700 K. This is contrast to single phase compounds which exhibit similar behaviour on heating and cooling. We correlate these anomalies in the electrical resistivities of multiphase compounds to the variation in phase composition at high temperatures. The inhomogeneous distribution of dopants between the matrix and secondary phase is found to be crucial in the electronic transport properties of the multiphase compounds. These results can lead to further advances in designing composite Pb-chalcogenides with high thermoelectric performance.

Highlights

The search for high efficiency bulk thermoelectric materials for waste heat recovery has focussed on mid-range temperature (500-900 K) thermoelectric materials,[1,2,3,4,5] PbTebased alloys, which exhibit the highest thermoelectric conversion efficiencies amongst current generation thermoelectric materials for both n-type[6] and p-type[1,7,8] compounds
The selected compositions are located at the p-type (Na-doped) bulk quaternary (PbTe)-rich side of the PbTe-PbS pseudo-binary system.[15]
The purity, crystal structure and chemical composition of the samples were studied by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and are reported in detail elsewhere.[16]

Summary

Introduction

The search for high efficiency bulk thermoelectric materials for waste heat recovery has focussed on mid-range temperature (500-900 K) thermoelectric materials,[1,2,3,4,5] PbTebased alloys, which exhibit the highest thermoelectric conversion efficiencies amongst current generation thermoelectric materials for both n-type[6] and p-type[1,7,8] compounds. G; Wang, Heng; Gibbs, Zachary M.; Pei, Yanzhong; Dou, S X.; and Snyder, G. Abstract The electrical resistivity curves for binary phase compounds of p-type lead chalcogenide (PbTe)(0.9−x) (PbSe) 0.1 (PbS) x, (x = 0.15, 0.2, 0.25), which contain PbS-rich secondary phases, show different behaviour on heating and cooling between 500-700 K.

Results

Conclusion