Search

The resistance of single-walled carbon nanotube (SWNT) bundles has been investigated by two-terminal measurements. We find that the time dependence of resistance (dR/dt) exhibits different behaviors at different currents. At low currents, a positive dR/dt is observed. However, dR/dt shows a negative sign when the applied current exceeds a critical current (I-c). I-c coincides with the current when the sample begins to emit light. The variation of dR/dt can be interpreted as the thermal effects owing to Joule heating in the SWNTs. Our lighting SWNTs sample has a small change in resistance and exhibits high stability.

In this paper, we report that the electrical conductance of single-walled carbon nanotubes networks decreases when the nanotubes are illuminated by camera flash in high vacuum up to 10(-6) Torr. The decreasing conductance shows step-like characteristics at each illumination. The magnitude of conductance change step reduces gradually after each illumination; finally, the conductance reaches saturation. Controlled experiments in air, oxygen and nitrogen gas indicate that mechanism for these observations is photodesorption of molecular oxygen from singled-walled carbon nanotubes.