Structural Modification of Carbon Nanotube Tip Using Focused Ion Beam

We report the structural modification of carbon nanotube (CNT) tip for Atomic force microscopy (SPM) based on ion beam irradiation. In general, CNT tip assembled by dielectrophoresis would often have non-vertical angle, very crooked shape or too lengthy one. Therefore, these tips should be modified to the appropriate shape to use as an AFM tip. We found that the ion beam could contribute to merge the bundled CNTs, to make the CNT diameter uniform as well as to make the wavy shape of CNT straight. In addition, we could cut the free-standing CNT on a Si tip using focused ion beam (FIB). From the atomic force microscope (AFM) measurement of 15 nm gold particles and DNA molecules, we showed that the CNT tip modified by FIB produced high resolution images as well as little wear by comparing with those of a conventional silicon tip