Field electron emission from single carbon nanorod fabricated by electron beam induced deposition

Individual carbon nanorod was fabricated on a tungsten needle tip by electron beam induced deposition. Precursor was phenanthrene (C ₄H₁₀) and deposition experiment was done using a scanning electron microscope at room temperature. Tungsten needle tip together with the as-deposited nanorod was mounted inside a specially designed transmission electron microscope (TEM) specimen holder and its field electron emission properties were investigated in situ. Relationship between micro-structure and emission property of the nanorod was established. It was found that the surface structure at the top of 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.