Reduction of the dark-current in carbon nanotube photo-detectors

Carbon nanotubes have been considered in recent years for future opto-electronic applications because of their direct band-gap and the tunability of the band-gap with the CNT diameter. The performance of infra-red photo-detectors based on carbon nanotube field-effect transistors is analyzed, using the non-equilibrium Greenpsilas function formalism. The relatively low ratio of the photo-current to the dark current limits the performance of such devices.We show that by employing a double gate structure this ratio can be significantly increased.