Dresden 2014 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
DS: Fachverband Dünne Schichten
DS 42: Thermoelectric Materials
DS 42.8: Vortrag
Donnerstag, 3. April 2014, 16:45–17:00, CHE 89
Phonon processes in silicon crystalline quantum wires with amorphous surface — Dmitrii V. Crismari1, Denis L. Nika1, •Vladimir M. Fomin2, Daniel Grimm2,3, and Oliver G. Schmidt2,3 — 1E. Pokatilov Lab., Dep. Theor. Phys., Moldova State University, MD-2009 Chisinau, Republic of Moldova — 2Institute for Integrative Nanosciences, IFW-Dresden, D-01069 Dresden, Germany — 3Material Systems for Nanoelectronics, Chemnitz University of Technology, D-09107 Chemnitz, Germany
Advancements in high-tech fabrication have attracted interest to the investigation of amorphous microstructures, e.g., Si-based microtubes and radial superlattices with amorphous silica layers [1]. We study phonons in crystalline Si quantum wires with amorphous surface using the Valence Force Field approach with stochastic parameters of interatomic interactions. The phonon thermal conductivity (PTC) is calculated taking into account the phonon-phonon and phonon-surface scattering. Non-zero-velocity phonons, which penetrate amorphous coating, are strongly scattered there and removed from the heat transport. A considerable suppression of the PTC is revealed for experimentally feasible structures. Even for wide (cross-section sizes of 0.5 to 1 µm) quantum wires with amorphous surface, the PTC is suppressed by a factor of 1.5 to 2 as compared with fully crystalline ones. The suppression significantly increases in quantum wires of smaller cross-section. The work was supported by Moldova State Project 11.817.05.10F. D.V.C. acknowledges the support by DAAD. XX [1] R. Songmuang, A. Rastelli, S. Mendach, and O. G. Schmidt, APL 90, 091905 (2007).