Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 73: Nanostructures at Surfaces: 1D and 2D Structures
O 73.7: Poster
Mittwoch, 18. März 2015, 18:15–21:00, Poster A
Structural and Transport Properties of Etched Silicon Nanowires — •Stefan Weidemann1, Maximilian Kockert1, Anna Mogilatenko2, Klaus Rademann3, and Saskia F. Fischer1 — 1Neue Materialien, Institut für Physik, Humboldt-Universität zu Berlin, D-12489 Berlin — 2Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, D-12489, Berlin — 3Nanostructured Materials, Institut für Chemie, Humboldt-Universität zu Berlin
Understanding thermal transport on the nanoscale is essential for the miniaturisation of electronic devices and for nanopatterned materials. Rough silicon nanowires (SiNWs) show decreased thermal conductivity 1. Structural and thermo-electric characterization of an individual nanowire still remains a challenge.
In our study we prepare SiNWs by two-step metal-assisted chemical etching, which allows fabrication on wafer scale [2]. Doping levels range from undoped Si, resistivity ρ> 1000 Ωcm, to highly boron-doped Si, ρ = 0.01 Ωcm, and the axial crystal orientation is (100). By controlling the etching conditions and the substrate selection the NW lengths (30−100 µ m) and surface morphology (solid, rough and porous) can be adjusted 3. Single SiNW in the diameter range from 200 - 400 nm are investigated. Electrical conductivities and the thermovoltage are measured on a platform designed in four-point geometry with heaters.
1 A. I. Hochbaum et al., Nature 451, 163 (2008).
2 S. Weidemann et al., arxiv:1410.3763 (2014) submitted.
3 G. Yuan et al., Jour. Phy. Chem C, 116, 13767 (2012).