One-step rapid synthesis of n-type Y-doped Mg3Sb2 by pulsed electric current sintering and investigation of its thermoelectric properties

Abstract

The one-step rapid synthesis of n-type Y-doped Mg3Sb2 semiconductors (Mg3Sb2Yx; x = 0.000–0.05) has been performed via a pulsed electric current sintering process using Mg, Sb, and Y2O3 starting powders. The synthesized samples are composed of an α-Mg3Sb2 phase and a trace MgO phase. Because of the Y doping into Mg3Sb2, the room-temperature electron concentration increases up to ~7.6 × 1019 cm−3, which is considerably higher than the maximum values obtained for previously reported Te-doped Mg3Sb2 (~2 × 1019 cm−3). In the samples with the composition of x = 0.01–0.03, a dimensionless thermoelectric figure of merit of ~1.0 at 773 K is achieved by increasing the value of the thermoelectric power factor.