Effect of Sn doping on the thermoelectric properties of ErNiSb-based p-type half-Heusler compound

The authors characterized polycrystalline samples of Sn-doped ErNiSb “ErNiSnxSb1−x (x=0, 0.01, 0.03, and 0.05)” to develop p-type half-Heusler thermoelectric materials. All samples prepared in this study exhibited positive Seebeck coefficients. With increasing Sn content x, the carrier concentration increased, leading to decreases in both electrical resistivity (ρ) and the Seebeck coefficient (S). Thermal conductivity (κ) values were at a similar level in all of the compositions. Sn-doping improved the thermoelectric figure of merit ZT(=S2T∕ρ∕κ) of ErNiSb; the maximum ZT value was 0.29 at 669K, obtained in the composition ErNiSn0.01Sb0.99.