Infrared Studies of the (1-x) PbTe – (x) PbSnS₂ System

Abstract

In this work we report on the infrared properties of the thermoelectric (1-x)PbTe-xPbSnS2 system with x=0.03, 0.06, 0.11 and 0.33. The results obtained by the analysis of the reflectivity spectra are discussed together with the structural and morphological characteristics obtained by XRD and SEM-EDS measurements. The system was found macroscopically homogeneous for x=0.03 and x=0.06 and phase separated for x=0.11 and x=0.33. The analyzed ~150cm-1 PbS impurity mode demonstrated a composition close to the PbTe0.98S0.02 for the major phase. The incorporation of PbSnS2 causes a reduction in plasma frequency (decrease in carrier frequency concentration) and an increase in carrier mobility.

PbTe–PbSnS2 thermoelectric composites: low lattice thermal conductivity from large microstructures

“…39 Based on the IR reflectivity spectra of the undoped (1 À x)PbTe-xPbSnS 2 system with x ¼ 0.03, 0.06, 0.11 and 0.33 we concluded that the composition of the matrix is close to PbTe 0.98 S 0.02 . 40 A high frequency dielectric constant 40 has been obtained for this composition, 41 which is the value of 3 N we used for our susceptibility effective mass calculations by means of eqn (2).…”