Electrical and optical transport of GaAs/carbon nanotube heterojunctions

Heterojunctions consisting of nanotubes and an industrialized semiconductor-GaAs have been produced, and their transport properties were studied. We found that the p-doped GaAs forms an ohmic contact with a nanotube but the n-doped GaAs/nanotube heterojunction is rectifying. Analysis of measurement results at various temperatures shows that tunneling transport plays an important role. We also observed photovoltaic effects in n-GaAs/nanotube junction with the illumination of a green laser or desk lamp.