Carbon nanotube-modified cantilevers for improved spatial resolution in electrostatic force microscopy

The resolution of electrostatic force microscopy (EFM) is enhanced when multiwalled carbon nanotubes are used as extensions on conventional silicon cantilevers. Multiwalled nanotubes provide robust, high aspect ratio, conducting tips that minimize topographic dependence of gradients in the capacitance between the tip/cantilever and the substrate. Comparison of simultaneously acquired topographical and EFM images taken at the intersection of overlapping electrodes of electrically biased Al-Al2O3-Al tunnel junctions confirm the improved performance. This enhancement enables us to determine the surface contact potential differences between individual nanotubes within a bundle with resolutions of 5 mV and 10 nm. (C) 1999 American Institute of Physics. [S0003-6951(99)02244-5].