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 12.19: Poster

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

Scanning force microscopy/spectroscopy studies of single wall carbon nanotubes including defects — •Makoto Ashino¹, Theophilos Maltezopoulos¹, Alexander Schwarz¹, Serge G. Lemay², Cees Dekker², and Roland Wiesendanger¹ — ¹Institute of Applied Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany — ²Department of Applied Physics and DIMES, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands

We observed single wall carbon nanotubes (SWCNT) on highly oriented pyrolytic graphite (HOPG) by scanning force microscopy in noncontact mode. The images were obtained under feedback control to maintain a constant frequency shift (Δ f) of the cantilever eigenfrequency [1]. While the image contrast depends on the bias voltages (V_b), the most prominent contrast was obtained around V_b = 0 V. In particular, the features corresponding to the SWCNT include very sharp peaks. We evaluated the voltage dependence of their relative heights. In addition, at fixed V_b, we measured the variation of Δ f on the tip−sample distance and characterized van der Waals and electrostatic forces between tip and the SWCNT and the HOPG substrate, respectively. Through the above evaluation we will discuss mechanical and electrostatic properties of the SWCNT and the observed defects.

[1] S. Morita, R. Wiesendanger, and E. Meyer, Noncontact Atomic Force Microscopy, Springer (2002).