Photocurrent amplification at carbon nanotube-metal contacts

The generation of photocurrent at single-walled carbon nanotube (SWNT)-electrode contacts at zero bias was determined. The current produced can be amplified significantly by a factor of 4-7 upon application of a bias and, higher currents are always achieved at the electrode opposite to that with positive bias. It was found that the current build-up at negative bias is faster by a factor of 6-7 as compared to that of positive-bias operation. The results suggest that the electrostatic potential within nanotubes is highly sensitive to external electric fields at the junction region.