ELECTRICAL MEASUREMENTS ON SUBMICRONIC SYNTHETIC CONDUCTORS - CARBON NANOTUBES

The synthesis of very small samples has raised the need for a drastic miniaturization of the classical four-probe technique in order to real ize electrical resistance measurements. Two methods to realize electri cal contacts on very small fibers are described here. Using classical photolithography the electrical resistivity of a submicronic catalytic chemical vapour deposited filament is estimated. Scanning tunneling m icroscopy (STM) lithography allowed to attach small gold contacts to a small bundle (diameter 50 nm) of carbon nanotubes. This bundle is fou nd to exhibit a semimetallic behavior at higher temperature and an une xpected drop of the electrical resistivity at lower temperature.