Dresden 2014 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 35: Poster I: Application of thin films; Focus session: Sensoric micro and nano-systems; Focus Session: Sustainable photovoltaics with earth abundant materials; Graphen (joint session with TT; MA; HL; DY; O); Ion and electron beam induced processes; Layer properties: electrical, optical, and mechanical properties; Magnetic/organic interfaces, spins in organics and molecular magnetism; Micro- and nanopatterning (jointly with O); Organic electronics and photovoltaics (jointly with CPP, HL, O); Thermoelectric materials
DS 35.67: Poster
Mittwoch, 2. April 2014, 17:00–20:00, P1
Atomistic calculation of thermoelectric properties of Si nanowires — Igor Bejenari and •Peter Kratzer — Fakultät für Physik and Center for Nanointegration (CeNIDE), Universität Duisburg-Essen, Duisburg, Germany
In contrast to the bulk materials conventionally used in thermoelectrics, nanostructured materials offer the possibility to design thermoelectric devices with improved efficiency by exploiting the quantum confinement of electrons and phonons on the nanoscale. In this case, a fully atomistic simulation considering both the electron and phonon band structures as well as electron-phonon interaction is required to estimate thermoelectric properties.
We study thermoelectric properties of Si square nanowires with <100> crystalline orientation taking into account atomistic electron-phonon interaction. In our model, facets <010> and <001> are passivated by hydrogen and there are Si dimers on the nanowire surface. The electronic structure was calculated by using the sp3-spin-orbit-coupled atomistic second-nearest-neighbor tight-binding model. The phonon dispersion and density of states were calculated in framework of Brenner’s model. Based on Fermi’s golden rule, the electron-phonon scattering rate was obtained by combining the electron and phonon eigenstates. Both elastic and inelastic scattering processes are taken into consideration. We used a solution of linearized Boltzmann transport equation to calculate transport characteristics. For the Si nanowire with a thickness of 1.6 nm at room temperature, the electron mobility is 422 cm2V−1s−1 and ZT=0.8 at n=1020 cm−3.