The current-voltage (I-V) characteristic of single-wall carbon nanotubes (SWNT) network was investigated at low temperatures. At T∼1.6K, S-shaped negative differential resistance (NDR) was observed, which was systematically examined under the variation of temperature, magnetic field in transverse direction and distances between probes. S-shaped NDR was explained by the nondestructive impact ionization of carriers and the resulting formation of inhomogeneous spatial structures such as high-current filaments. Critical electric fied for impact ionization was estimated to be about 1V/cm.
- Fullerenes and derivatives
- Transport measurements