Resistivity and Field Electron Emission of Nanowires Formed by Electron Beam Induced Chemical Vapor Deposition

摘要

Self-standing iron nanowires were fabricated at the apex of a tungsten needle tip by electron beam induced deposition.This sharp needle tip which adhered to the nanowire can be moved with a stepping motor and piezo-driving device,and was attached inside a specially designed transmission electron microscope specimen holder.A copper conductor substrate,with which the approaching nanowires will build up a closed electric circuit,was set on the holder.The tungsten needle tip accompanied with the EBICVD nanowires made contact with the substrate and then a voltage was applied between the two electrodes.Resistivity values of the examined nanowires,by a devised Lock-in-Amplifier circuit,range from 0.1 Ωm to 10~(-3)Sim.Our investigation might have implications in the fabrication and characterization of nano-electronics device.Precursor with phenanthrene(C4H10)was used and the deposition experiment was done using a scanning electron microscope at room temperature.It was found that the surface structure at the top of the nanorod,such as a small protrusion within only several nanometers scale,has significant influence on the field emission property.An emission current of several tens of nano-ampere flowing through this nanorod could induce resistance heating.In several minutes,this thermal energy could transform the original amorphous carbon into a graphite-like structure embedded with fullerenes.The turn-on voltage of the graphite-like nanorod was about 11 V less than that of the original amorphous case.