AgSn[Bi1-xSbx]Se-3: Synthesis, Structural Characterization, and Electrical Behavior

Abstract

Herein, we report the synthesis, characterization, and electrical properties of lead-free AgSnm[Bi1-xSbx]Se2+m (m = 1, 2) selenides. Powder X-ray diffraction patterns and Rietveld refinement data revealed that these selenides consisted of phases related to NaCl-type crystal structure. The microstructures and morphologies of the selenides were investigated by backscattered scanning electron microscopy, energy-dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy. The studied AgSnm[Bi1-xSbx]Se(2+m )systems exhibited typical p-type semiconductor behavior with a carrier concentration of approximately similar to+1020 cm(-3). The electrical conductivity of AgSnm[Bi1-xSbx]Se2+m decreased from similar to 3.0 to similar to 10-3 S.cm(-1) at room temperature (RT) with an increase in m from 1 to 2, and the Seebeck coefficient increased almost linearly with increasing temperature. Furthermore, the Seebeck coefficient of AgSn[Bi1-xSbx]Se-3 increased from similar to+36 to +50 mu V.K-1 with increasing Sb content (x) at RT, while its average value determined for AgSn2[Bi1-xSbx]Se-4 was approximately similar to+4.5 mu V.K-1.