Berlin 2015 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 36: Poster Session I

DS 36.81: Poster

Donnerstag, 19. März 2015, 09:30–12:00, Poster A

Influence of interfaces on the thermoelectric efficiency — •Michael Bachmann, Jonas Schäfer, Michael Czerner, and Christian Heiliger — I. Physikalisches Institut, Justus Liebig University Giessen, D-35392, Germany

We present our results on phonon- and electron transport across nanostructured interfaces and the resulting impact on the thermoelectric properties. For the electron transport we focus our investigations on the energy filtering at grain boundaries [1]. Our results are based on a model that we developed to describe electron transport in nanograined materials. The grain boundaries are described using the model introduced by Seto [2]. It is believed that such barriers can increase the efficiency of thermoelectric materials by energy filtering effects. We conclude that electrostatic barriers play no role for thermoelectric devices. For the phonon transport we use an atomistic Greens function method to investigate the phonon scattering Si isotope-multilayer. Our calculations [3] show that a periodic arrangement of the layer-system cannot decrease the phonon thermal conductivity substantially, whereas a random arrangement of the layer-system can lead to a strong decrease in the phonon conductivity. We also show that small deviations from the periodic arrangement are enough to end up in the random regime.

M.Bachmann, M. Czener and C.Heiliger, Phys. Rev. B 86, 115320

[2] J. Seto, J.Appl. Phys. 46 5247 (1975)

[3] M Bachmann et al 2014 Semicond. Sci. Technol. 29 12400