Single Walled Carbon Nanotubes for Scanning Force Microscopy

Henriette Jensenius^1,2, Matthew Osbourn², Dionne C. G. Klein^2,3, Tjerk H. Oosterkamp³, Frans D. Tichelaar⁴, Thomas Schmidt², and Anja Boisen¹

(1) Mikroelektronik Centret, DTU, 2800 Lyngby
(2) Department of Biophysics, LION, Leiden University, The Netherlands
(3) Interface Physics group, LION, Leiden University, The Netherlands
(4) Department of Materials Science and Technology, Delft University of
Technology, The Netherlands

We investigate the use of single walled carbon nanotubes (SWNT) as probes in Scanning Force Microscopy (SFM) of biological molecules. SWNTｹs can be a few nanometers thin and have a high aspect ratio. The SWNTｹs are both strong and flexible and the end of the tubes is well suited for specific chemical modification. These properties make it possible to probe different functional domains within a single biological macromolecule. Using a technique developed in the lab of C. M. Lieber [1] we attach SWNTｹs to SFM cantilever tips. SWNT grown on a silicon surface will remain standing if the growth is stopped when they are less than ~500 nm long. When a cantilever tip is scanned over the surface a SWNT can be picked up, protruding from the apex of the tip. The adsorbed SWNT can be shortened by applying an electrical potential between the tube and a conducting surface. The SWNTtips are studied with transmission electron microscopy.

[1] J. H. Hafner et al., J. Phys. Chem. B 105, 743-746 (2001).