Zero dark leakage current single-walled carbon nanotube diodes

We describe measurements of diode leakage currents in p-n and p-i-n diodes formed along individual single-walled carbon nanotubes (SWNTs) in the ranges well below the direct detection limit. When cooled, these diodes exhibit leakage currents down in the range of 10⁻²⁵ A or equivalent to 1 electron/19 days. To verify our measurement of such low leakage currents, we use the photovoltaic property under varying temperatures to extract the dark diode leakage currents. Since nanotubes are sensitive in the near IR spectrum, these diodes show promise as zero dark current noise, near-infrared detectors.