D. Platzek1, A. Zuber1,C. Stiewe1, G. Bähr1, P. Reinshaus2, E.Müller1
1GermanAerospace Center (DLR), Institute of MaterialsResearch, D-51170 Köln, Germany
2Martin-Luther-UniversitätHalle-Wittenberg, FG Angewandte Physik, D-06099 Halle (Saale), Germany
The common principle of scanning theSeebeck coefficient at the surface of a thermoelectric material is based onsimultaneous measurement of two thermo-voltages, aroused by a temperaturegradient between a tip-shaped hot microprobe and the sample. A pointed probemounted to a three-dimensional micro-positioning system allows thedetermination of the individual thermoelectric power of each single sampleposition. This method has only been working at ambient temperature, so far.
Recent improvement ofthe measuring device by the implementation of a cooling/heating system led toexpansion of the sample temperature range spreading about 30 K below and aboveroom temperature and enables computer controlled repeating scans on the samplesurface at different stabilised temperature levels, set in pre-defined steps.In this way, along with the sample homogeneity, the temperature dependence nearroom temperature of the Seebeck coefficient can be determined at differentlocations at the sample, facilitating an advanced analysis of thermoelectricmaterials.