Interdisziplinäres Zentrum für Materialwissenschaften
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Interdisziplinäres Zentrum für Materialwissenschaften
Nanotechnikum Weinberg
Heinrich-Damerow-Str. 4,
D-06120 Halle, Germany
Phone: +49 345 55 28471
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Katrin Bertram, Matthias Stordeur, Frank Heyroth, Hartmut S. Leipner
Dynamic in situ observations of electrical and structural changes in thin thermoelectric (Bi0.15Sb0.85)2Te3 films
J. Appl. Phys. 106 (6) (2009), 063711

Thin films of (Bi0.15Sb0.85)2Te3 were prepared by dc magnetron sputter deposition on different substrates. It is well known that thermal treatment of as-deposited p-type (Bi0.15Sb0.85)2Te3 films leads to an enhancement of the power factor. Whereas up to now only the initial (as deposited) and the final (after annealing) film stages have been investigated, here, the dynamic changes of sputter-deposited film properties have been observed by in situ measurements. The enhancement of the power factor shows a significant dependence on thermal treatment. The best thermoelectric films have been prepared at a substrate temperature of 170 °C, with a power factor of 24.4  µW/(cm K2). The changes in the Seebeck and Hall coefficients are caused by the enhancement in the Hall mobility after annealing. In situ x-ray diffractometry shows the generation of additional Te in dependence of the temperature. This is also confirmed by energy-dispersive x-ray microanalysis and the corresponding mapping in a scanning electron microscope. It is supposed that the locally well-defined Te enrichment is the reason for the improvement in the integral film transport properties.

Keywords: in situ, electric properties, Bi2Te3, preparation, annealing, conduction, temperature dependence, Hall, X-ray diffraction, EDX, mapping, stoichiometry
© 2009 American Institute of Physics

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