LAUSR

Lead Selenide (PbSe) has been used for thermoelectric materials since 1950’s due to its high thermoelectric figure of merit zT (~0.8 at ~700K where zT = S2σT/κ, which depends on the Seebaeck coefficient [the thermopower] S, absolute temperature T, electrical conductivity σ, and thermal conductivity κ) [1]. To extend the temperature range for thermoelectric materials, i.e., to increase the zT, defect engineering by reducing the thermal conductivity has been the most popular approach. The defect engineering used in PbTe(Se) polycrystallites such as the large area grain boundaries, non-stoichiometric of Pb or Te(Se) depletion region and dopant precipitates has been widely studied [2]. However, literature for PbSe and Pb1-xSnxSe have primary focused on special physical properties of topological crystalline insulator [3], and the study of formation of defects in PbSe and Pb1-xSnxSe single crystals has been scarce. A microstructure study of the intrinsic defects in PbSe and Pb1-xSnxSe single crystals was thus undertaken using conventional and aberration corrected TEM/STEMs.