Microscale Seebeck Scanning of Polycrystalline Samples of N-Type AgPb₁₈SbTe₂₀ and P-Type AgPb₉Sn₉SbTe₂₀

Abstract

We prepared polycrystalline-sintered samples of n-type AgPb₁₈SbTe₂₀ and p-type AgPb₉Sn₉SbTe₂₀ and performed the microscale Seebeck scanning examination under room temperature conditions. Despite both samples appeared to be homogeneous by Energy Dispersive X-ray (EDX) and X-ray Diffraction (XRD) analyses, both samples contained apparently a microscale distribution of the Seebeck coefficient as observed by Seebeck microprobe analysis. The degree of the Seebeck coefficient distribution became larger in the order of PbTe, AgPb₁₈SbTe₂₀, and AgPb₉Sn₉SbTe₂₀, indicating that an increase in the number of compositional elements of the materials led to a broader distribution of the Seebeck coefficient values. The statistical analysis of the Seebeck coefficient distribution of p-type AgPb₉Sn₉SbTe₂₀ indicated a homogeneous phase seemed to appear only at the lowest Seebeck coefficient values (slightly above 50 μV/K).