Ohmic contact junction of carbon nanotubes fabricated by in situ electron beamdeposition

Abstract

We present experimental evidence of in situ fabrication of multi-walled carbon nanotubejunctions via electron beam induced deposition. The tip-to-tip interconnection of thenanotubes involves the alignment of two nanotubes via a piezodriven nanomanipulator andnano-welding by electron beam deposition. Hydrocarbon contamination from the pump oilvapour of the vacuum system of the TEM chamber was used as the solder; this is superiorto the already available metallic solders because its composition is identical to the carbonnanotube. The hydrocarbon deposition, with perfect wettability, on the nanotubesestablishes strong mechanical binding between the two nanotubes to form an integratedstructure. Consequently, the nanotubes cross-linked by the hydrocarbon solder producegood electrical and mechanical connections. The joint dimension was determined by thesize of the electron beam, which results in a sound junction with well-definedgeometry and the smallest junction size obtained so far. In situ electric measurementshowed a linear current–voltage property for the multi-walled nanotube junction.