Tapping mode scanning force microscopy in water using a carbon nanotube probe

An improved technique for obtaining tapping mode scanning force microscopy (TMSFM) images of soft samples submerged in water is described. This techni que makes use of a carbon nanotube several microns in length mounted on a c onventional silicon cantilever as the TMSFM probe. The sample is covered by a shallow water layer and during imaging only a portion of the nanotube is submerged. This mode of operation largely eliminates the undesirable effec ts of hydrodynamic damping and acoustic excitation that are present during conventional tapping mode operation in liquids and leads to high-quality TM SFM images. Because of their low bending force constants, carbon nanotubes are ideal for gentle imaging of soft samples. Because of their small (5-20 nm) diameter and cylindrical shape they provide excellent lateral resolutio n and are ideal for scanning high aspect ratio objects. (C) 1999 Elsevier S cience B.V. All rights reserved.