Tailoring thermoelectric transport in (La,Sm)-doubly filled skutterudite thin films via controlled annealing

In view of the electrical transport optimization in thermoelectric films, a p- and a n- conducting doubly-filled skutterudite belonging to the system (La,Sm) y (Fe x Ni 1– x ) 4 Sb 12 , were deposited as thin films by pulsed laser deposition, and subsequently annealed under different conditions to assess how the post-deposition treatment affects structural and electrical properties. X-ray diffraction data reveal the occurrence of a preferential orientation along the planes belonging to the {310} family, which tends to disappear with increasing the annealing temperature. Within the considered span, the lowest (423 K) and the highest (523 K) annealing temperatures are the most suitable for achieving optimal power factors in the p- and n- type film, respectively. This evidence is discussed in terms of competition between degradation of the film and progressive structural reorganization toward long-range order. The study underscores the need for a careful choice of the post-deposition thermal treatments aimed at the optimization of the electrical properties and power factor of filled skutterudite thin films.