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DS: Fachverband Dünne Schichten

DS 10: Thermoelectric and Phase Change Materials

DS 10.3: Vortrag

Montag, 1. April 2019, 17:15–17:30, H39

Phonon modes and thermal conductivity in Si/SiO₂ multishell nanotubes — C. I. Isacova¹, A. I. Cocemasov¹, D. L. Nika¹, O. G. Schmidt², and •V. M. Fomin^1,2 — ¹E. P. Pokatilov Laboratory of Physics and Engineering of Nanomaterials, Moldova State University, Chisinau MD-2009, Republic of Moldova — ²Institute for Integrative Nanosciences, Leibniz IFW Dresden, Dresden D-01069, Germany

Theoretical atomistic study of thermal transport is conducted for Si/SiO₂ multishell nanotubes, which model rolled-up Si/SiO₂ nanostructures. Phonon modes are obtained within Lattice Dynamics Theory. Thermal conductivity in Si/SiO₂ nanotubes, as calculated using Boltzmann Transport Equation within the relaxation-time approximation, is lower than that in Si nanowires with the same lateral dimensions due to the acoustical mismatch of the materials and a stronger phonon confinement. A large number of phonon modes are scattered on Si/SiO₂ interfaces, what enhances the effect of the boundary scattering mechanism on thermal conductivity of multishell nanotubes. Thermal conductivity is found to decrease almost linearly as a function of the number of Si/SiO₂ bilayers in multishell nanotubes. The present work is supported by the DFG grant no. FO 956/4-1.