Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 25: Transport
HL 25.2: Talk
Monday, March 14, 2011, 16:00–16:15, POT 151
Thermoelectric properties of strained silicon — •Nicki F. Hinsche1, Ingrid Mertig1,2 und Peter Zahn1 — 1Martin-Luther-Universität, Institut für Physik, Von-Seckendorff-Platz 1, 06120 Halle/S. — 2Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany
Starting from bulk silicon, we study the change in thermoelectric properties due to symmetry breaking in rolled-up and layered Si [1] which might lead to nanostructured thermoelectrics. Valley splitting in strained Si caused by tetragonal distortion was studied recently with respect to the enhancement of electron mobility [2]. Our results show that the tetragonal distortion has a strong influence on the electronic transport properties. The electronic structure is calculated self consistently within the framework of density functional theory. The transport properties are studied in the diffusive limit applying the Boltzmann theory in relaxation time approximation [3]. In detail, the anisotropy of the electrical conductivity, the thermopower and the resulting powerfactor in the in-plane and off-plane directions are studied in dependence on strain, doping level and temperature [4]. It is shown, that the powerfactor at a given temperature can be enhanced slightly by strain for p-doping, while no enhancement is obtained for n-doping.
[1] F. Cavallo, W. Sigle, and O. Schmidt. Journal of Appl. Phys. 103, 116103 (2008). [2] T. Dziekan, P. Zahn, V. Meded, and S. Mirbt. Phys. Rev. B 75, 195213 (2007). [3] I. Mertig. Reports on Progress in Physics 62, 237 (1999). [4] N.F. Hinsche, I. Mertig and P. Zahn. submitted, 2010.