Electroluminescence in carbon nanotubes

Electroluminescence in long-channel, ambipolar carbon nanotubes is highly localized in a small tube region where electron- and hole currents overlap. This region, reminiscent of a pn junction in a light-emitting diode, but produced without static dopants, can be moved along the entire carbon nanotube simply by adjusting the voltage at a uniform backgate. The movement of the spot, its size, the spectrum of the emitted light, and the efficiency of infrared generation allows a much better understanding of the electronics in ambipolar carbon nanotube field-effect transistors. © 2005 American Institute of Physics.