Dresden 2009 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 33: Thermoelectric Thin Films and Nanostructures I
DS 33.5: Vortrag
Donnerstag, 26. März 2009, 11:45–12:00, GER 38
Potential & Seebeck Microprobe -- Imaging of electrical and thermoelectric materials properties on the microscale — •Pawel Ziolkowski1, Gabriele Karpinski1, Dieter Platzek2, Christian Stiewe1, Ralf Hassdorf1, and Eckhard Müller1 — 1German Aerospace Center (DLR), Institute of Materials Research, 51170 Cologne — 2Physics Technology -- Development and Consulting (PANCO), 56218 Mülheim-Kärlich
Recent developments turned the Potential & Seebeck Microprobe (PSM) into a powerful tool for electrical functional materials characterisation. A wide spectrum of applications has been demonstrated including thermoelectric cobalt antimonide and bismuth telluride thin films as well as nanostructured thick films. The principle involves a heated probe tip positioned at the surface of a sample coupled to a heat sink. The sample is scanned by mechanically touching and again lift-off from the surface at each position. The tip is heating up the sample in a microvicinity, forming a locally focused temperature gradient. By several measuring circuits, thermovoltages and the temperature drop over the gradient region are recorded, yielding the local Seebeck coefficient. With an electrical current feedthrough, the potential profile over the sample is monitored. Microresolving images both of the Seebeck coefficient and the potential obtained in a single run provide information on functional effects of the distribution of chemical components, phases, alloy constituents, or dopants. The method is particularly helpful in studying functionally segmented or graded materials and suitable for low resistivity materials due to its high-sensitive signal detection limit.