Synthesis, Crystal Structure, and High Temperature Transport Properties of p‑Type Cu2Zn1–xFexSnSe4

Iron substituted Cu2Zn1–xFexSnSe4 stannites were synthesized by reaction of the constituent elements and subsequent annealing, followed by densification by hot-pressing. The compositions for each specimen were confirmed with a combination of Rietveld refinement and elemental analysis. Refinement results indicated that only the 2a site was occupied by Zn and Fe. High temperature transport properties were measured from 300 to 800 K. The electrical resistivity and thermal conductivity decrease with increasing Fe content. For the lower Fe content specimens with x = 0.2 and 0.4, the electrical properties are strongly temperature dependent, unlike that of the higher Fe content specimens (x = 0.6 and 0.8). A maximum ZT value of 0.46 was obtained at 800 K for Cu2Zn0.4Fe0.6SnSe4.