The Study Of Carbon Nanotube’s Modification By Focused Ion Beam Irradiation And Its Healing Strategies

Recently, carbon nanotubes (CNT) have got extensive attention and number ofresearches, because of its unique structure and excellent performance. It is consideredto be the ideal probe for scanning probe microscope due to its excellent mechanicalproperties and high aspect ratio. However, there are still certain problems in thefabrication of CNT probe. Studies have shown that focused ion beam (FIB) irradiationcan well control CNT probe’s orientation, however, the irradiation will inevitablyinduce some unnecessary defects to CNT. These have been urgent problems that howto achieve precise control of the nanotube probe’s angle and length, and how tominimize the introduction of secondary damages in the process of regulation. Thispaper aims to get a more systematic understanding about the orientation parameterssetting of CNT probe, so FIB Ga+ions irradiation experiments were conducted. Whileheat treatment experiments were also conducted for the healing of irradiation-inducedCNT defects. And it is meaningful to get good CNT probe with both good orientationand structure.CNT’s internal structure changes can be well characterized by Raman spectroscopy,and high resolution transmission electron microscopy (HRTEM) can provide a moreintuitive understanding to CNT’s morphology.More detailed studies about FIB Ga+ions irradiation effects to CNT and annealingheat treatment to irradiation-induced CNT defects were characterized by Ramanspectroscopy (with excitation wavelength:785nm) and HRTEM. Our studies haveshown that big ion irradiation energy could cause more damages to CNT and quicklyincrease the defects of carbon nanotube. Therefore, we can conclude that smallamount of energy can well control the orientation process of CNT probe by inducingsimple defects, such as vacancy and adatoms, which will weaken CNT probe’smechanics and stiffness. While big amount of ion energy will easily cause somecomplex defects and instability of the probe.Since defects induced by ion irradiation are inevitable, our studies have shown thatannealing heat treatment can promote the chemical bonds reorganization of CNTs,and make structure reach a new steady state, and then reduce the defects.