Fs-pulsed laser deposition of PbTe and PbTe/Ag thermoelectric thin films

摘要

For the first time, thermoelectric thin films were fabricated by femtosecond pulsed laser depositionud(fs-PLD) that represents a challenging technological solution for this application since it provides a correct film stoichiometry compared to the starting target, capability of native nanostructuring and a high deposition rate. In particular, this paper shows a preliminary work on PbTe and PbTe/Ag thin films deposited at different substrate temperatures by fs-PLD from a microcrystalline PbTe target.udStructural, morphological and compositional characterizations of the deposited films were performed to demonstrate the formation of films composed by crystalline nanograins (about 35 nm size) and characterized by a correct stoichiometry.udA remarkable deposition rate of 1.5 nm/s was evaluated. The electrical conductivity and the Seebeckudcoefficient (thermopower) were measured as a function of operating temperature to derive the thermoelectric power factor that was found to be less than a factor 2 with respect to the bulk materials. Finally, a discussion about the influence of compositional and structural properties of the deposited films on the related thermoelectric performances was presented.