One-step rapid synthesis of n-type Y-doped Mg_3Sb_2 by pulsed electric current sintering and investigation of its thermoelectric properties

摘要

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 alpha-Mg3Sb2 phase and a trace MgO phase. Because of the Y doping into Mg3Sb2, the room-temperature electron concentration increases up to similar to 7.6 x 10(19) cm(-3), which is considerably higher than the maximum values obtained for previously reported Te-doped Mg3Sb2 (similar to 2 x 10(19)cm(-3)). In the samples with the composition of x = 0.01-0.03, a dimensionless thermoelectric figure of merit of similar to 1.0 at 773 K is achieved by increasing the value of the thermoelectric power factor. (C) 2019 Elsevier B.V. All rights reserved.