The invention provides sharpened multi-walled nanotubes and methods for sharpening multi-walled nanotubes. The methods of the invention use an electron beam to machine the multi-walled nanotube to the desired dimensions. The invention provides sharpened boron nitride nanotubes where the radius of the end of the sharpened tip is less than about 10 nm.
ACKNOWLEDGEMENT OF GOVERNMENT SUPPORT
 This invention was made with Government support under contract number DEFG02-91-ER45439 awarded by the U.S. Department of Energy (DOE). The United States Government has certain rights in the invention.