Dresden 2009 – scientific programme

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DS: Fachverband Dünne Schichten

DS 35: Thermoelectric Thin Films and Nanostructures II

DS 35.3: Talk

Thursday, March 26, 2009, 16:15–16:30, GER 38

Complete thermoelectric characterization of thin films — •Jan D. König — Fraunhofer IPM; Heidenhofstr. 8; 79110 Freiburg; Germany

An enhancement of the thermoelectric performance is needed for a wider use of thermoelectricity. The developments of nanostructured materials such as thin film superlattices have shown a considerable increase of the thermoelectric figure of merit. Such developments are based on the measured values of the physical transport properties and naturally on the accuracy of the measurement itself! So it is necessary to have a closer look on the commonly used thermoelectric measuring techniques and on new cross-plane thermopower and electrical conductivity measuring techniques for thin films. Some comments on standard thermopower and electrical conductivity measurements in the in-plane directions are given. The advantage and disadvantage of the 3Omega methode and the TDTR-methode will be investigated. The Völklein methode will be discussed exemplary as a bridge method to determine the in-plane thermal conductivity. The most challenging problems are the measurement of the cross-plane electrical conductivity and thermopower. The complexity of such measurements are illustrated at some principle approaches. These considerations will give a better understanding of the complexity of thermoelectric measurement techniques for thin films and should be a guideline for an accurate measurement of the thermoelectric properties for material development and verification of the theoretical nanoconcepts for an enhancement of the thermoelectric performance.