Ohmic contact junction of carbon nanotubes fabricated by<i>in situ</i>electron beam deposition

Abstract

We present experimental evidence of in situ fabrication of multi-walled carbon nanotube junctions via electron beam induced deposition. The tip-to-tip interconnection of the nanotubes involves the alignment of two nanotubes via a piezodriven nanomanipulator and nano-welding by electron beam deposition. Hydrocarbon contamination from the pump oil vapour of the vacuum system of the TEM chamber was used as the solder; this is superior to the already available metallic solders because its composition is identical to the carbon nanotube. The hydrocarbon deposition, with perfect wettability, on the nanotubes establishes strong mechanical binding between the two nanotubes to form an integrated structure. Consequently, the nanotubes cross-linked by the hydrocarbon solder produce good electrical and mechanical connections. The joint dimension was determined by the size of the electron beam, which results in a sound junction with well-defined geometry and the smallest junction size obtained so far. In situ electric measurement showed a linear current–voltage property for the multi-walled nanotube junction.