Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 27: Scanning probe techniques II
O 27.10: Vortrag
Dienstag, 28. März 2006, 18:00–18:15, WIL B321
Temperature dependence of point-contact friction on silicon — •Lars Jansen1,2, André Schirmeisen1,2, Hendrik Hölscher1,2, and Harald Fuchs1,2 — 1Institute of Physics, University of Muenster, Wilhelm-Klemm-Str. 10, 48149 Muenster — 2CeNTech, Center for Nanotechnology, Gievenbecker Weg 11, 48149 Muenster
Due to the rising importance of the tribological properties of silicon in industrial applications like micro-electro mechanical systems (MEMS), the friction between two silicon bodies is of high interest. In order to investigate the tribological properties, we have measured the frictional forces between a Si-tip and a Si(111)-surface at different sample temperatures in the range of 30 K to 300 K by cooling the sample with a flow cryostat, using liquid nitrogen and liquid helium. The measurements are performed with a commercial Atomic Force Microscope under ultra high vacuum conditions. The temperature dependence of the friction coefficient, given by the ratio of friction to load, shows a large variation by a factor of 3-9 within the investigated temperature range with a maximum around 100 K. Furthermore, we found a drastic change in the velocity dependence of the friction. Above 150 K the friction is virtually independent of the velocity in the range from 200 nm/s to 20.000 nm/s, while below 150 K the friction is proportional to logarithm of the velocity. These findings are of great interest for the design and functionality of MEMS devices.