Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 12: Postersitzung (Struktur und Dynamik reiner Oberfl
ächen, Grenzfl
äche fest-flüssig, Nanostrukturen, Teilchen und Cluster, Halbleiteroberfl
ächen und Grenzfl
ächen, Zeitaufgelöste Spektroskopie, Rastersondentechniken, Methodisches)

O 12.40: Poster

Montag, 24. März 2003, 18:00–21:00, P1

Dissipation measurements on metal surfaces using non-contact AFM — •Domenique Weiner, Andre Schirmeisen, and Harald Fuchs — Physikalisches Institut, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster

The atomic force microscope (AFM) in the non-contact mode provides the opportunity to separate information about long-range and short-range forces. Furthermore, dissipation processes can also be investigated. Especially the temperature dependence of this effect is an interesting aspect.

We are able to measure dissipation processes on metal surfaces (e.g. Au (111)) with metallized tips. For this purpose we prepare the single-crystal surface by sputtering it with an argon ion-beam under ultra-high vacuum (UHV) conditions. Then we anneal the surface by resistive heating for about 20 minutes. Without breaking the vacuum conditions we transfer the sample into the UHV-VT-AFM (Omicron). This two-chamber-apparatus enables us to measure in the dynamic mode at variable temperatures (VT). We study the dissipation signal and the frequency-shift-curves simultaneously from room temperature up to 600 K. Commercial silicon cantilevers with a spring constant of about 40 N/m are used. The tips are covered with a thin Au-film of about 100nm thickness.

We perform spectroscopy measurements, i.e. frequency shift and dissipation as a function of tip-sample separation, to gain quantitative values, which are compared to other dissipation measurements [1].

[1] B. C. Stipe, H. J. Mamin, T. D. Stowe, T. W. Kenny, and D. Rugar, Phys. Rev. Lett. 87, 096801, 2001.