ZnSb-based thermoelectric thin films by PLD and combined PLD-sputtering system

Full text: The request of thermoelectric thin films is involving increasingly several research groups for their attractive low-power applications and the possibility to fabricate flexible and efficient devices. Among the thermoelectric materials, ZnSb represents a promising candidate in the temperature range 400-600 K since it is a cheap, non-toxic and potentially high-performing material. The feasibility of Pulsed Laser Deposition (PLD) as a powerful deposition technique for nanostructuring thermoelectric films has been demonstrated. The deposition of p-type and n-type doped ZnSb thin films has been performed by fs-PLD and by a fs-PLD/DC sputtering co-deposition system in order to compare the dopant inclusion within the ZnSb matrix, aimed at finding the recipe able to maximize the films thermoelectric performance. Structural, compositional and thermal characterizations have been carried out to study and to demonstrate thermal and chemical stability of the samples. Electronic performance has been analysed by carrier concentration, mobility, electrical resistivity and the Seebeck coefficient, thus obtaining the evaluation of the power factor as a function of the doping. Finally, preliminary measurements of thermal conductivity by TDTR (Time-Domain ThermoReflectance), obtained by a fs-laser pump-and-probe setup, are discussed. (author)