Effect of Sn-Substitution on Thermoelectric Properties of Copper-Based Sulfide, Famatinite Cu₃SbS₄

Abstract

Copper-based sulfide is an attractive material for Earth-abundant\nthermoelectrics. In this study, we demonstrate the effect of Sn-substitution on\nthe electrical and thermal transport properties of fematinite Cu3SbS4 from 300\nto 573 K. The carrier concentration is controlled in the range from 4 \\times\n10^18 to 8 \\times 10^20 cm^-3 by Sn-substitution. The density-of-states\neffective mass is found to be ~3.0 me, assuming the single parabolic band\nmodel. The direct-type optical band gap is ~0.9 eV, which is consistent with\nthe density functional theory calculation. The dimensionless figure of merit\nreaches 0.1 for Sn-doped samples at 573 K.\n