Dresden 2009 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 33: Thermoelectric Thin Films and Nanostructures I

DS 33.2: Vortrag

Donnerstag, 26. März 2009, 11:00–11:15, GER 38

Thermoelectric transport in periodic 1D stacks of InAs/GaAs quantum dots — •Vladimir M. Fomin^1,2,3 and Peter Kratzer¹ — ¹Fachbereich Physik and Center for Nanointegration (CeNIDE), Universität Duisburg-Essen, Germany — ²TFVS, Departement Fysica, Universiteit Antwerpen, Belgium — ³PMS, Department of Theoretical Physics, State University of Moldova, Chişinău, Moldova

Superlattices (SLs) of InAs/GaAs quantum dots (QDs) are presently of interest for possible thermoelectric applications. Due to the quantum confinement of electrons and phonons, such SLs are expected to provide an improved figure-of-merit. The present work is aimed at the investigation of a periodic 1D stack of InAs quantum disks in GaAs. Electron minibands for a 3D SL of InAs/GaAs QDs are calculated using the tight-binding approach. The essential features of the obtained minibands, e.g. the distribution of the probability density in the xy-plane, can be understood within the Kronig-Penney model of a periodic 1D stack of quantum disks. Solution of the dispersion relation for acoustic phonons in a 1D SL with the parameters of the 3D SL of InAs/GaAs QDs confirms the accuracy of a model of an effective medium. Using the obtained electron wave functions and the phonon fields, the relaxation time is calculated and the electric and thermoelectric coefficients for a periodic 1D stack of InAs/GaAs quantum disks are analyzed as a function of their geometric characteristics. V.F. acknowledges the support by the ESF through Exchange Grant No. 2157 within the activity ’Arrays of Quantum Dots and Josephson Junctions’.