Thermoelectric Performance of Tetrahedrite (Cu 12 Sb 4 S 13 ) Thin Films: The Influence of the Substrate and Interlayer.

In the present work, tetrahedrite Cu 12 Sb 4 S 13 thin films were deposited on various substrates via aerosol-assisted chemical vapor deposition (AACVD) using diethyldithiocarbamate complexes as precursors. A buffer layer of Sb 2 O 3 with a small lattice mismatch to Cu 12 Sb 4 S 13 was applied to one of the glass substrates to improve the quality of the deposited thin film. The buffer layer increased the coverage of the Cu 12 Sb 4 S 13 thin film, resulting in improved electrical transport properties. The growth of the Cu 12 Sb 4 S 13 thin films on the other substrates, including ITO-coated glass, a SiO 2 -coated Si wafer, and mica, was also investigated. Compared to the films grown on the other substrates, the Cu 12 Sb 4 S 13 thin film deposited on the SiO 2 -coated Si wafer showed a dense and compact microstructure and a larger grain size (qualities that are beneficial for carrier transport), yielding a champion power factor (PF) of ∼362 μW cm -1 K -2 at 625 K. The choice of substrate strongly influenced the composition, microstructure, and electrical transport properties of the deposited Cu 12 Sb 4 S 13 thin film. At 460 K, the highest zT value that was obtained for the thin films was ∼0.18. This is comparable to values reported for Cu-Sb-S bulk materials at the same temperature. Cu 12 Sb 4 S 13 thin films deposited using AACVD are promising for thermoelectric applications. To the best of our knowledge, the first full thermoelectric characterization of the Cu 12 Sb 4 S 13 thin film is performed in this work.