Regensburg 2010 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 14: Thermoelectric Thin Films and Nanostructures II

DS 14.2: Vortrag

Dienstag, 23. März 2010, 14:30–14:45, H8

Thermoelectric efficiency in stacks of n-type InAs/GaAs quantum dots — Vladimir M. Fomin¹ and •Peter Kratzer² — ¹Institut für Integrative Nanowissenschaften (IIN), Leibniz-Institut für Festkörper- und Werkstoffforschung (IFW) Dresden, D-01069, Dresden — ²Fakultät für Physik und Center for Nanointegration (CeNiDE), Universität Duisburg-Essen, D-47048, Duisburg

We investigate the effect of the electron miniband energy spectrum of periodic 1D stacks of self-assembled InAs/GaAs quantum dots (QDs) with different geometrical parameters on their electronic transport employing the Boltzmann transport equation. The electron minibands are calculated within tight-binding and Kronig-Penney models. The transport relaxation time reveals a significant dispersion as a function of the wave vector in the stacking direction. The chemical potential is related to the concentration of electrons of the conduction band taking into account the minibands and a continuum. From the numerical analysis of the electric and thermal conductivities, the Seebeck coefficient and the figure-of-merit, we conclude that a 1D stack of QDs achieves a geometry-controlled enhanced efficiency as a thermoelectric converter in certain windows of the donor concentration. Reducing the QD height for a fixed stacking period is favourable for an increase of the figure-of-merit.

A fruitful collaboration with O. G. Schmidt and A. Rastelli and a financial support under the DFG SPP 1386 and the ESF Exchange Grant 2157 within the activity ‘Arrays of Quantum Dots and Josephson Junctions’ are gratefully acknowledged.