Thermoelectric materials are used in thermoelectric generators that convert a temperature gradient into a voltage.
To characterize the performance of a thermoelectric material, the so-called figure of merit (ZT) is used to characterize the performance of a thermoelectric material.
To calculate the figure of merit thermal conductivity, electrical conductivity and the Seebeck coefficient must be known.
Metallic thin films have lower thermal and electrical conductivities compared to the corresponding bulk materials, while the Seebeck coefficient is less affected, resulting in higher ZT values.
Metallic thin films are frequently used in industry, for example in the manufacture of integrated circuits.
The electrical conductivity, thermal conductivity and Seebeck coefficient were measured in a temperature range from 225 K to 375 K on a nanolayer of gold (Au) with a thickness of 100 nm prepared by DC magnetron sputtering.
ZT was calculated from these parameters.
The measured thermal and electrical conductivity of this thin film was approximately half that of the bulk material.
The results, which showed a clear influence of the classical size effect, were checked and were in perfect agreement with the Wiedemann-Franz law.
