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Systematic study of carbon nanotubes (CNTs) characteristics, as well as fabrication of CNTs based devices, require development of reliable technologies for successive growth or deposition, manipulation, contacting, processing, and measurements of electrical, optical, magnetic and other properties of individual nanotubes or their films. For this, integration of these technologies and analysis of their compatibility is extremely important. It is necessary to determine the conditions when the processes employed result in negligible (or at least, controllable) changes in the properties of processed nanotubes. In this work we study the effects of ion irradiation, promoted by focused ion beam (FIB), on the electrical properties of suspended CNTs. In this way, special electrodes were prepared by lithography and FIB processes. These techniques allowed preparing a device for electrical measurements in CNTs. The FIB process was used to deposit narrow lines of Pt between the electrodes and to make cuts to fabricate deep valleys between Pt lines. This kind of structures was used to obtain suspended CNTs deposited between metal electrodes using a dielectrophoresis method. Electrical contacts between CNTs and metal (Pd) electrodes were improved with Pd or Ni deposition by electroless process ou by FIB-deposited Pt. Electrical properties of suspended CNTs were measured before and after ion irradiation, using 2 and 4 terminals methods. |