Nanoelectrode Scanning Probes from Fluorocarbon-Coated Single-Walled Carbon Nanotubes
We have developed a method to coat single-walled carbon nanotubes attached to AFM tips with conformal fluorocarbon polymer films formed in an inductively coupled plasma reactor. The polymer provides a chemically inert and electrically insulating outer layer and mechanically stabilizes the attached nanotube sufficiently to enable imaging in liquids without the need for an intervening adhesive. Electrical pulse etching of the insulating coating exclusively at the nanotube tip end results in well-defined highly conductive nanoelectrodes. For these probes, the conductive properties of the nanotubes are not affected by the coating. Some nanoelectrodes behave as rectifying diodes, which may be developed into novel molecular devices integrated onto scanning probes.
Additional Information© 2004 American Chemical Society. Received June 29, 2004; Revised Manuscript Received July 29, 2004. Publication Date (Web): August 19, 2004. The authors thank Lawrence Wade, Jordan Gerton, and David Lopez for helpful discussions. We acknowledge Dr. P.-L-M. Noeske, Fraunhofer Institute, IFAM, Bremen for expertise in the measurements of XPS spectra at high resolution and at low fluorocarbon film thicknesses. We also acknowledge the help of Shannon Lewis with XPS measurements and Carol Garland with TEM imaging. This work was supported by Caltech startup funds and by Arrowhead Research.
Supplemental Material - nl048991ssi20040729_081150.pdf