Thermoelectric Performance of Tetrahedrite (CuSbS) Thin Films: The Influence of the Substrate and Interlayer.

In the present work, tetrahedrite CuSbS thin films were deposited on various substrates via aerosol-assisted chemical vapor deposition (AACVD) using diethyldithiocarbamate complexes as precursors. A buffer layer of SbO with a small lattice mismatch to CuSbS 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 CuSbS thin film, resulting in improved electrical transport properties. The growth of the CuSbS thin films on the other substrates, including ITO-coated glass, a SiO-coated Si wafer, and mica, was also investigated. Compared to the films grown on the other substrates, the CuSbS thin film deposited on the SiO-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 K at 625 K. The choice of substrate strongly influenced the composition, microstructure, and electrical transport properties of the deposited CuSbS thin film. At 460 K, the highest 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. CuSbS thin films deposited using AACVD are promising for thermoelectric applications. To the best of our knowledge, the first full thermoelectric characterization of the CuSbS thin film is performed in this work.