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O: Fachverband Oberflächenphysik

O 73: Nanostructures at Surfaces: 1D and 2D Structures

O 73.8: Poster

Wednesday, March 18, 2015, 18:15–21:00, Poster A

Preparation of undoped and boron-doped silicon nanowires — •Maximilian Kockert¹, Stefan Weidemann¹, Klaus Rademann², and Saskia F. Fischer¹ — ¹Neue Materialien, Humboldt-Universität zu Berlin, 12489 Berlin, Germany — ²Nanostrukturierte Materialien, Humboldt-Universität zu Berlin, 12489 Berlin, Germany

Silicon nanowires (SiNWs) are potentially efficient thermoelectric materials because of the reduced phonon contribution to the thermal conductivity and they are interesting for biochemical applications due to their big surface-to-volume ratio [1]. In this work we prepare SiNWs of undoped silicon substrates (electrical resistivity ρ > 1400 Ω cm) and boron-doped silicon substrates (ρ = 0.01 - 0.02 Ω cm) by metal-assisted chemical etching. We analyse the influence of the concentration of hydrogen peroxide, light and temperature on the wire length [2]. Scanning electron microscope investigations show that an increase of one of these etching parameters lead to longer SiNWs, when the etching time is constant. Further measurements show that after three hours of etching the wire length l of undoped SiNWs reaches l = 75 µ m and of boron-doped l = 43 µ m.

[1] A. Boukai et al., Nature 415, 168 (2008).

[2] S. Weidemann et al., arXiv:1410.3763 (2014).