Thermoelectric properties of Zintl phase compounds of Ca1-xEuxZn2Sb2 (0 ≤ x ≤ 1).
Tessera Alemneh Wubieneh1,2,3,4*, Pai-Chun Wei2, Szu-yuan Chen1,3,4, Yang-Yuan Chen2
1Department of Physics, National Central University, Taoyuan, Taiwan
2Institute of Physics, Academia sinica, Taipei, Taiwan
3MST program, TIGP, Academia sinica, Taipei, Taiwan
4Institute of atomic and molecular science, academia sinica, Taipei, Taiwan
* presenting author:Tessera Alemneh Wubieneh,
P-type Ca1-xEuxZn2Sb2 (0 ≤ x ≤ 1) polycrystalline specimens were prepared by direct solid-state reaction of elements followed by appropriate annealing, grinding and spark plasma sintering for densification. The thermoelectric (TE) properties of Zintl phase Ca1-xEuxZn2Sb2 were investigated by the measurements of resistivity, Seebeck coefficient and thermal conductivity from 300 to 720 K. All Eu doped specimens show more than 50% decrease in electrical resistivity, while their Seebeck coefficient value only slightly decease as compared with that of the pristine CaZn2Sb2. Furthermore, a reduction of thermal conductivity was achieved by the additional phonon scatterings of Eu dopants. The structural disorder produced by the incorporation of multiple cations significantly increased the thermoelectric dimensionless figure of merit for all Europium substituted samples. Within this series Ca1-xEuxZn2Sb2, x = 1 shows a best thermoelectric properties with ZT=1.

Keywords: Thermoelectric , Sebbeck cofficient, Zintl phase