AVS 51st International Symposium
    Nanometer-scale Science and Technology Monday Sessions
       Session NS-MoM

Paper NS-MoM10
Electrical Characterization of Carbon Welds between Multiwalled Carbon Nanotubes

Monday, November 15, 2004, 11:20 am, Room 213D

Session: Carbon Nanotubes-Electrical Properties
Presenter: P. Rice, NIST
Authors: P. Rice, NIST
S.E. Russek, NIST
P. Kabos, NIST
R.H. Geiss, NIST
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Nanometer scale electronics based on carbon nanotubes have the potential to revolutionize the electronics industry by reducing circuit sizes dramatically and by increasing operational speed due to inherent properties of the nanotubes. Currently there are very few methods of connecting carbon nanotubes to electronics. The most prevalent so far is using the scanning electron microscope (SEM) focused at a junction between the nanotube and the circuit and growing a carbon contamination buildup we call a weld. This buildup, typical in most SEMs, is caused when the electron beam cracks carbon compounds commonly found on the surface of the sample and in the SEM atmosphere. The subsequent free and chemically active carbon quickly attaches itself to nearby surfaces and builds into mounds securely bonding the nanotube to the surface. Using microlithographic test structures we have measured the electrical characteristics of the nanotube and the welds from dc to MHz frequencies. These measurements have shown a semiconductor behavior of the nanotube and weld combination. To separate the weld electrical properties from the nanotube electrical properties we have built test structures that measure contact resistance between unwelded nanotubes and the same nanotubes after welding. Also, the molecular characteristics of the welds are very dependent on SEM parameters such as electron beam energy, alignment of the electron beam, vacuum pressure inside the SEM chamber, and molecular species near the beam impingement on the sample. We will correlate the structure of these welds to electrical properties as influenced by the SEM deposition parameters using transmission electron microscopy.