Berlin 2012 – scientific programme
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DS: Fachverband Dünne Schichten
DS 41: Thermoelectric materials III: Heterostructures (Focused session – Organizers: Meyer, Heiliger)
DS 41.6: Talk
Friday, March 30, 2012, 10:45–11:00, H 2032
Electric Characterization of Si/Ge Superlattices — •Markus Trutschel1, Katrin Bertram1, Bodo Fuhrmann1, Alexander Tonkikh2, Peter Werner2, and Hartmut S. Leipner1 — 1Martin-Luther-Universität Halle-Wittenberg, Interdisziplinäres Zentrum für Materialwissenschaften, Heinrich-Damerow-Str. 4, D-06120 Halle, Germany. — 2Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
Si/Ge superlattices are expected to have an increased figure of merit due to their two dimensional structure. The enhancement in the figure of merit can be attributed to a decreased thermal conductivity due to phonon scattering at the interfaces between the Si/Ge layers. For this reason applications are aspired in cross plane direction.
The measurement of electrical properties in cross plane direction of thin films with thicknesses in the nanometer range is strongly affected by measurement uncertainties. In this work, we studied the requirements of the electrical conductivity measurement cross plane using a modified transmission line model (TLM). For this purpose, a suitable mesa structure for TLM measurements was developed. In order to obtain more precise results, a finite element model was performed to simulate the current density distribution in the sample. Additionally we present experimental results in comparison to the calculated values.
We thank the BMBF for financial support.