Dresden 2014 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 42: Thermoelectric Materials
DS 42.7: Vortrag
Donnerstag, 3. April 2014, 16:30–16:45, CHE 89
Phonon thermal conductivity in cross-section modulated Si wires: A transition from nano- to microscale regime — Alexandr I. Cocemasov1, Denis L. Nika1, •Vladimir M. Fomin2, Daniel Grimm2,3, and Oliver G. Schmidt2,3 — 1E. Pokatilov Lab., Dep. Theor. Phys., Moldova State University, Chisinau MD-2009, Rep. of Moldova — 2Institute for Integrative Nanosciences, IFW-Dresden, D-01069 Dresden, Germany — 3Material Systems for Nanoelectronics, Chemnitz University of Technology, D-09107 Chemnitz, Germany
Periodically modulated nanowires are perspective for thermoelectric applications due to low values of phonon thermal conductivity [1-2]. At present, modulated profiles can be fabricated at the scale of tens and hundreds nm. We have studied a transition of phonon thermal transport in cross-section modulated Si wires from nano- to microscale regime, considering phonon spectra for modulated nanowires obtained within an atomistic model of lattice dynamics and scattering of bulk Si phonons on external faces of the modulated segments for microstructures. For a Si wire of a square cross-section with side d, modulation depth of d/10, modulated segment width of d/4 and distance between neighboring modulated segments of 3d/4, the transition from the nano- to microscale transport regime at room temperature occurs at ∼ 100 nm. The work was supported by Moldova State Projects 11.817.05.10F and 12.819.05.18F. A.I.C. acknowledges the support by DAAD.
[1] D. L. Nika, A. I. Cocemasov, C. I. Isacova, A. A. Balandin, V. M. Fomin, O. G. Schmidt, PRB 85, 205439 (2012). [2] D. L. Nika, A. I. Cocemasov, D. V. Crismari, A. A. Balandin, APL 102, 213109 (2013).