TFA – thermoelectric thin film – thermoelectric properties – metals&alloys
Full ZT – Figure of Merit Characterization of a metallic thermoelectric thin film / Seebeck coefficient / electric conductivity / thermal conductivity
Thermoelectric materials are used in thermoelectric generators converting a temperature gradient in a voltage. To characterize the performance of a thermoelectric material the so called figure of merit (ZT) is used.
In order to calculate the figure of merit, thermal conductivity, electric conductivity and the Seebeck coefficient have to be known. Compared to the corresponding bulk materials, metallic thin layers show lower thermal and electric conductivities while the Seebeck coefficient is less effected resulting in higher ZT-values. Metallic thin films are widely used in industry for example in the fabrication of integrated circuits.
Electrical conductivity, thermal conductivity and Seebeck coefficient were measured in a temperature range of 225 K to 375 K on a gold (Au) nanofilm of 100 nm thickness prepared by DC magnetron sputtering. From these parameters ZT was calculated. Measured thermal and electric conductivity of this thin film were approx. half of those of the bulk material. The results showing a clear influence of classical size effect were checked and agreed perfectly with the Wiedemann-Franz-law.